Fix crash in interpretKeyEvents.

cmd.match could return null, but was immediately being indexed. Added a
null check.
Fixed layout value warning to accept other valid layout values
Added sanity checks into grid layout computation
Fixed menu UI tests by specifying primary mouse button
Explicitly specifying mouse event pageX and pageY for drag and drop tests
Merge pull request #1234 from jameschao/layout_warning_fix

Fixes for various failing tests
Merge pull request #1230 from sproutcore/team/fairbanksg/interpret-key-events-crash

Fix crash in interpretKeyEvents.
Added originalHeight and originalWidth to view frames
Improved scroll view scaling to pivot around center of viewable area
Added tests for scroll view scaling changes