This commit removes the internal property maps from the GraphInterface
class, and makes all property maps external by default. The internal
property maps were moved to the python layer.

Now graphml files properly contain all the supported value types, which
are all perfectly preserved when read (floating point data is now saved
in hexadecimal format). Several other improvements were made, such as
the ability to read and write to python file-like objects.

It is also now possible to have arbitrary python object properties, and
store them persistently (which is done internally with the pickling
interface).

vector<bool> was totally abolished, since its implementation is quite
broken. See: http://www.gotw.ca/publications/N1211.pdf and
http://www.gotw.ca/publications/N1185.pdf Now a uint8_t (aka. char) is
used in graph properties instead of a bool.

Graph types can now be fully pickled (this may not be feasible
memory-wise if the graph is too large, since the whole XML
representation is dumped to a string before it is saved on disc).

This commit splits libraph_tool into different libraries:
 
   - libgraph_tool_core
   - libgraph_tool_clustering (*)
   - libgraph_tool_community (*)
   - libgraph_tool_correlations (*)
   - libgraph_tool_distance (*)
   - libgraph_tool_generation (*)
   - libgraph_tool_layout (*)
   - libgraph_tool_misc (*)
   - libgraph_tool_stats (*)

It also adds the python sub-module 'test', which provides extensive unit
testing of the core functionality. The core library is fully functional
and all test pass successfully.

(*) -> module needs to be ported to new refactoring, and does not yet build

This is a huge commit which completely refactors the metaprogramming
engine which generates and selects (at run time) the graph view type and
the desired algorithm implementation (template instantiation) that runs
on it.

Things are laid out now as following. There exists a main underlying
graph type (GraphInterface::multigraph_t) and several other template
classes that mask it some way or another, in a hierarchic fashion:

     multigraph_t -> filtered_graph (edges only, vertices only, both)
         |                               |           |           |
         |                               |           |           |
         |-------(reversed_graph)--------|-----------|-----------|
         |                               |           |           |
         \------(UndirectedAdaptor)------------------------------/

The filtered_graph filters out edges and/or vertices from the graph
based on some scalar boolean property. The reversed_graph reversed the
direction of the edges and, finally, the UndirectedAdaptor treats the
original directed graphs as undirected, transversing the in- and
out-edges of each vertex indifferently. Thus, the total number of graph
view types is 12. (The option --disable-graph-filtering can be passed to
the configure script, which will disable graph filtering altogether and
bring the total number down to 3, to reduce compile time and memory
usage)

In general, some specific algorithm, implemented as a template function
object, needs to be instantiated for each of those types. Furthermore,
the algorithm may also depend on other types, such as specific
property_maps. Thus, the following scheme is used:

    struct my_algorithm // algorithm to be implemented
    {
        template <class Graph, class PropertyMap>
        void operator()(Graph *g, PropertyMap p, double& result) const
        {
            // ...
        }
    };

    // in order for the above code to be instantiated at compile time
    // and selected at run time, the run_action template function object
    // is used from a member function of the GraphInterface class:

    double GraphInterface::MyAlgorithm(string prop_name)
    {
        double result;
        boost::any vprop = prop(property, _vertex_index, _properties);
        run_action<>()(*this, bind<void>(my_algorithm(), _1, _2,
                                         var(result)),
                       vertex_scalar_properties())(vprop);
        return result;
    }

The whole code was changed to reflect this scheme, but now things are
more centralized and less ad-hoc code needed to be
written. Unfortunately, due to GCC's high memory usage during template
instantiations, some of the code (namely all the degree correlation
things) had to be split in multiple compilation units... Maybe this will
change in the future if GCC gets optimized.

This commit also touches other parts of code. More specifically, the way
filtering gets done is very different. Now we only filter on boolean
properties, and with the above scheme, the desired implementation runs
with the correct chosen type, and no implicit type conversions should
ever happen, which would have a bad impact on performance.

The check for parallel edges was cleaned up and abstracted into a
function, and other minor things were changed. Code comments were added
to places where it might have been hard to understand.

Vertices and edges can be accessed from the graph class, as such:

    import graph_tool
    g = graph_tool.Graph()
    for v in g.vertices():
        for e in v.out_edges():
           # do something...

Additionally, the --edit-{vertex|edge|graph}-property was ported to the
new interface, and is working again, as it used to.

The Vertex and Edge class no longer have the 'get_property' and
'set_property' method. They'll be replaced by a new method of accessing
property maps.

Line breaks at column 80 were added, and all trailing whitespace was deleted. Code
comments were modified and some more were added.

* removed exeption throwing in scalarS to improve performance


git-svn-id: https://svn.forked.de/graph-tool/trunk@113 d4600afd-f417-0410-95de-beed9576f240

git-svn-id: https://svn.forked.de/graph-tool/trunk@101 d4600afd-f417-0410-95de-beed9576f240

git-svn-id: https://svn.forked.de/graph-tool/trunk@59 d4600afd-f417-0410-95de-beed9576f240

git-svn-id: https://svn.forked.de/graph-tool/trunk@58 d4600afd-f417-0410-95de-beed9576f240

* removed neighbour selectors (not really needed at all). Improves compilation speed, memory usage and binary size!
* removed clustering specific code in favour of more generic property code
* added GetEdgeHistogram()
* renamed some functions/options ("degree"->"vertex")


git-svn-id: https://svn.forked.de/graph-tool/trunk@9 d4600afd-f417-0410-95de-beed9576f240

removing edge selectors, since the same behaviour can be obtained by using the --undirected and --reverse filters, as long as the in-degree is also seen when the undirected filter is turned on


git-svn-id: https://svn.forked.de/graph-tool/trunk@7 d4600afd-f417-0410-95de-beed9576f240

git-svn-id: https://svn.forked.de/graph-tool/trunk@1 d4600afd-f417-0410-95de-beed9576f240