fix wx keyboard shortcuts
fix wx keyboard shortcuts

wx < 2.9.2 prefers CmdDown to check for a modifier key, where as later
versions prefer ControlDown.
This fixes a problem with ctrl+click being eaten as a right click on OS
X.

liulion/mayavi,dmsurti/mayavi,alexandreleroux/mayavi,alexandreleroux/mayavi,dmsurti/mayavi,liulion/mayavi