Adding default value for selectable in column options, optimizing canCellBeSelected

Copied from merge pull request #540 of mleibman on March 1, 2013.
Added support for predefined group values to DataView.

Copied from mleibman March 1, 2013 commit. His original comments copied
here:

New grouping info properties:
- predefinedValues - An array containing the grouping values for which
groups should be included even if they are empty.
- aggregateEmpty - Whether aggreggators should be run on empty groups.
Remove usage on $.browser for jquery 1.9.0

mleibman made the same change on March 4, 2013
Improved Checkbox editor ValueChanged behavior.

Copied from mleibman pull request #542 on March 5, 2013.
Optimize DataView flattenGroupedRows()

Copied from mleibman commit on March 7, 2013.
Add option to hide totals row.

Copied from pull request #550 on mleibman master. March 08, 2013.
Vendor prefixes, duplicate properties

Copied from Mar 19, 2013 commit to mleibman master.