Merge pull request #302 from mjafin/master

Disambiguation for RNA-STAR fixed: nM tag changed to NM
Avoid issues with numpy 1.7/1.8 discrepency in automated conda installation. Fixes #304
Annotate using the gffutils db if it exists.

Remove mygene method as calling out to external sources can be
problematic in some compute environments.

Resolves #300. Thanks to @mjafin.