Add functionality to AutoTooltips to optionally work for header cells. Add tests for AutoTooltips.
Add example to demonstrate AutoTooltips.
Add link to AutoTooltips test.
Fix test and clean up.
Clean up file.
Merge pull request #611 from mckramer/autotooltips2

Enable AutoTooltips plugin to work with header cells
Fix #418 - header menu icons not visible in FF when used with sortable columns
Fix #613 - set grid focus when the range is selected
Merge remote-tracking branch 'upstream/master'