More 2.3 Fixes

This PR is based on https://github.com/modxcms/Gallery/pull/39 so please merge this one before merging mine.

- Fixes windows
- Adds fileupload xtype (available in 2.3) where applicable with BC for 2.2.x
- Adds primary-button classes where applicable
- Fix various smaller UI glitches
- Adjust data/browser view (details panel)
=), thanks @danyaPostfactum, didn't know that ExtJS method, still suck at it =D! And yes, you're absolutely right, as fileuploadfield was added in 2.3 it would return false in 2.2!