Travis : Use clang on OSX
Travis : Use clang on OSX

This is the default in the SConstruct file, but was getting overridden unintentionally in our Travis setup. Also remove troublesome XCode 8.2 build for now.

hradec/gaffer,boberfly/gaffer,ImageEngine/gaffer,boberfly/gaffer,ivanimanishi/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,appleseedhq/gaffer,hradec/gaffer,ivanimanishi/gaffer,johnhaddon/gaffer,johnhaddon/gaffer,appleseedhq/gaffer,lucienfostier/gaffer,hradec/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,hradec/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,boberfly/gaffer,ImageEngine/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,lucienfostier/gaffer,ivanimanishi/gaffer,boberfly/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,hradec/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,ivanimanishi/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,appleseedhq/gaffer,ImageEngine/gaffer