TinyMCE:
- Tighten up button styles, add :hover for .mce-active buttons.
- Pad only the first toolbar row and remove the padding in both toolbars if the editor doesn't have a DFW mode.
Part props avryl, see #27279

git-svn-id: https://develop.svn.wordpress.org/trunk@27978 602fd350-edb4-49c9-b593-d223f7449a82