UI changes and optimizations

This PR improves the UI and contains internal optimizations
- The UI has been improved and ported to the halo styles
- The main view contains tabs for fast access to channels and recordings
- The actionbar is used throughout all screens
- More programs will automatically be loaded when the user reaches the end of program list
- The recordings are grouped into tabs
- Orientation changes remember the selected tab and items
- and much more...

Note: This PR contains the PR #19, #20, #21 and #22.