Implemented RenderMan shader parameter activation via annotation expressions.
Implemented RenderMan shader parameter activation via annotation expressions.

An activator is defined by a global annotation of this form :

	pragma annotation "activator.name.expression" "pythonExpression"

The python expression may reference current parameter values by name, and also use the connected( "parameterName" ) function to query whether or not a parameter is connected.

Activators are then assigned to specific parameters using annotations of this form :

	pragma annotation "parameterName.activator" "name"

paulondc/gaffer,chippey/gaffer,goddardl/gaffer,boberfly/gaffer,appleseedhq/gaffer,chippey/gaffer,andrewkaufman/gaffer,chippey/gaffer,cedriclaunay/gaffer,boberfly/gaffer,hradec/gaffer,chippey/gaffer,hradec/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,cedriclaunay/gaffer,appleseedhq/gaffer,johnhaddon/gaffer,hradec/gaffer,ivanimanishi/gaffer,davidsminor/gaffer,appleseedhq/gaffer,cedriclaunay/gaffer,lucienfostier/gaffer,hradec/gaffer,ivanimanishi/gaffer,andrewkaufman/gaffer,boberfly/gaffer,paulondc/gaffer,goddardl/gaffer,appleseedhq/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,davidsminor/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,paulondc/gaffer,paulondc/gaffer,johnhaddon/gaffer,ivanimanishi/gaffer,davidsminor/gaffer,davidsminor/gaffer,hradec/gaffer,ImageEngine/gaffer,boberfly/gaffer,GafferHQ/gaffer,goddardl/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,GafferHQ/gaffer,goddardl/gaffer,ImageEngine/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,ivanimanishi/gaffer,cedriclaunay/gaffer,GafferHQ/gaffer