mouseButtonNumber

[David Bovill]

This is the param that mouseUp and mouseDown pass. From the docs:

The mouseButtonNumber specifies which mouse button was pressed:
    * 1 is the mouse button on Mac OS systems and the left button on Windows
and Unix systems.
    * 2 is the middle button on Unix systems.
    * 3 is the right button on Windows and Unix systems and Control-click on
Mac OS systems.

I want to emulate this in a script - is there a built in function, or does
someone have a utility function for this that has been tested
cross-platform?