IMouseMod.L always true on MacOS about iplug2 HOT 1 OPEN

Thanks for the report.

This looks like it needs wider checking than the PR as it also affects getMouseRight and we need to ensure parity with windows. There might be some discussion to be had about what should happen for mouseups for instance (as this is a possible mechanism for a dev to differentiate left/right mouse ups. It would also be a little bit of detective work to figure out what was happening before I made the restructure that introduced these methods.

The PR looks like a sensible proposition as a starting point, but we need to ensure consistency. (As a more minor matter, PRs that match formatting are easier to merge directly and in this case the opening curly bracket has been moved on the method)

This issue relates to #635 and they should be resolved together

from iplug2.