pressMouseButton()/releaseMouseButton() synthetic events should generate pointerdown/pointerup in addition to mousedown/mouseup

[wkeese]

IE (IE11 Win 8.1) uses synthetic mouse events since environmentType.brokenMouseEvents is true. The problem is that (similar to #17) pressMouseButton() and releaseMouseButton() fire synthetic mousedown (and mouseup) events, but not pointerdown (and pointerup) events.

This is from leadfoot's simulateMouse() code.

See also #83 and #17.