Fixed regular expression for removing paste_data_images

The existing regex only picked up images where the src attribute immediately followed the tag opening. However, you could have an image tag like <img alt="something" src="data:image...">.
Add the 'mce-contextmenu' class to the contextmenu so that css can target this menu separately.
Fixed missing text color in default skin
Move var in fix for #6410
Merge pull request #258 from jashua212/bug_6410

Move var in fix for #6410
Merge pull request #256 from tractionsoftware/contextmenu-class

Add the 'mce-contextmenu' class to the contextmenu
Merge pull request #257 from black-silence/master

Fixed missing text color in default skin
Merge branch 'patch-5' of github.com:danransom/tinymce into danransom-patch-5
Added tests for paste_data_images and fixed some code formatting.
Fixed some UI bugs and broken unit tests.
Fixed various unit tests.