Manually implement mouse movementXY in HTML5 mousemove events when the browser does not provide the data. Fixes part 2) from issue #2219.
Implement support for Webkit mouse wheel events. Add new interactive mouse test. Checked on OSX Safari 6.0.5. Fixes #2219.
Add an automated version of the html5 mouse test in browser test suite.
Merge pull request #2224 from juj/osx_mouse

OSX mouse support.