Refactored contexts for validation, added unit tests, enabled -plit for map.
Fixed a cut/paste error in unit test comment.
Removed outdated comment
Removed unnecessary NULL checks on delete.
Added unit test to intersect for gff files.
Added -split option to map help.
Merge pull request #33 from nkindlon/master

Refactored contexts for validation, added unit tests, enabled -plit for ...