Restrict travis builds to master and stable branches.
Restrict travis builds to master and stable branches.

dpoirier/django-all-access,iXioN/django-all-access,vyscond/django-all-access,iXioN/django-all-access,mlavin/django-all-access,dpoirier/django-all-access,mlavin/django-all-access,vyscond/django-all-access