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)