Provide sensible default camera manipulators in 2D interaction mode
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
I'm creating a pvpython application with ParaViewWeb, and it requires the interaction mode to be 2D/parallel projection style. It was a bit confusing that ParaView provided some nice sensible default camera manipulators for 3D interaction mode, but none for 2D.
I've attached a patch that provides the same 2D defaults that appear in the PV GUI application: left click to pan and right click to zoom. I think this is important for anyone creating pvpython apps that might want to use 2D interaction mode.