Fix bug with removing last vertex when fast == True

This fixes issue #305
6 jobs for master in 1862 minutes and 8 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Test
passed job_clang_amd64 #1701
amd64

05:58:00

passed job_clang_amd64_nosh #1705
amd64

05:31:45

passed job_clang_py2_amd64 #1703
amd64

05:28:12

passed job_gcc_amd64 #1700
amd64

05:09:51

passed job_gcc_amd64_nosh #1704
amd64

04:24:51

passed job_gcc_py2_amd64 #1702
amd64

04:29:26