UI improvements to DeskClock.

Fixes:
- "Dim" button moved to TR corner per spec.
- Next Alarm moved to TL corner per spec.
- Launcher button added (not yet wired).
- Battery indicator added to BR corner per spec.
- Drop shadow added to all text per spec.
- Layout now fills the portrait display vertically.

Known problems:
- No landscape layout
- Layout jumps when status bar disappears for dim mode
- No artwork yet
- Weather is a big orange box instead of, you know, weather