Remove grid header context menus.

A fix for #42 if you count closing your eyes as a fix. The genre column is only used in the Movie by Genre view.
Update change log for issue #42.
Merge pull request #67 from fyfe/fix-issue-42

Remove grid header context menus.
Upgrade to extjs 3.4.1.1 and remove extra files from extjs.
Replace the dark gray theme with the gray theme.