Button Re-write

This replaces PR #1216 

This includes new widget controlgroup which replaces buttonset
Current known issues 
 - [ ] Accordion Test Failures due to focus not working in phantom
 - [ ] Checkboxradio testfailure missing default element (@scott_gonzalez said it should not have one because it cant be sane ) this causes common tests to fail
 - [ ] Backcompat
 - [ ] Controlgroup icon only buttons 1px too short in chrome, firefox extra weird @jaspermdegroot think you could take a look?
 - [ ] demos/controlgroup/default.html As above, labels should demo something
 - [ ] demos/checkboxradio/default.html doesn't have the "command line" anymore, but still doesn't look like a demo. Labels should reflect some real world usecase.
 - [ ] demos/button/icons.html still looks like a visual test, not a demo

This is a bad test. It should specify which classes need to be there, like

```js
equal( button.attr( "class" ), "... ui-button ... " );
```

/cc @fnagel