Add unit test for cobra.Gene.remove_form_model
Add unit test for cobra.Gene.remove_form_model

This function raises an Exception while running (issue #119)

aebrahim/cobrapy,jeicher/cobrapy,zakandrewking/cobrapy,aebrahim/cobrapy,JuBra/cobrapy,zakandrewking/cobrapy,JuBra/cobrapy,jeicher/cobrapy,jerkos/cobrapy,jerkos/cobrapy