scintilla: Force the scrollWheel event to bypass NSScrollView
http://bugs.activestate.com/show_bug.cgi?id=99862

This makes we we can get deal with those events from JS rather than letting
NSScrollView do the scrolling for us (which doesn't work when we are using
fake scrollbars)

(integrated from komodo (trunk) change 81787 by marky)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13591 b87d16e7-d29f-4ee1-b5ec-817d645d335f