Added NvMTriTrophicTable
RemoveNodes allows secondary extinctions
Work on #24
Work on #23
Merge branch 'site_by_species'
Closed #24
Merge branch 'site_by_species'
Tweaks to helpfile and test for SiteBySpeciesMatrix. Closes #24.
Closes #23
merge branch 'secondary_extinctions'
Removed debugging code
Tweaked helpfiles. Closes #22
Closes #22
Closes #27