remoteeventhandler.send() checks for self.exited
close() ignores ClosedError
Minor fixes:
 - fixed deprecated use of param in generator/stimparamset
 - fixed double definition of MockCamera.sigParamsChanged
 - adjusted CCIV protocol arrangement
Added Camera.makeFrameTransform
MockCamera fixes to ensure cell signals are fixed relative to global
coordinates
Fix: remoteproxy.close() sets self.exited
Fixed pg.ViewBox.invertY() to immediately update view transform.
Do not use lambda in ImageItem sigRemoved callback--causes rare errors
GradientEditorItem menu fixes