Invoke ConfigureEvent in the vtkCocoaRenderWindowInteractor.

The RenderWindowInterctors on all builds except for Cocoa invoke a
ConfigureEvent when the RenderWindow size changes.  This patch adds
the event for Cocoa.

Change-Id: I1aabc2376dbb028c4bd23d32ecd2c2d67da17464
Merge topic 'cocoa-configure-event' into master

8cbaa9b3 Invoke ConfigureEvent in the vtkCocoaRenderWindowInteractor.