Prepare Eclipse project

Note: since this is a proof-of-concept, for simplicity I removed some
files which failed to compile. This affects the backup functionality.
Disable welcome message. See source for details.
Replaced default desktop configuration

Note: this is mainly needed since I was working with a Sony phone with
stock software. I also tested the configuration on XPeria ZL with CM 11.
Implement achievements/features

* all_apps: by default the app tray is not accessible. It will be
  available only after starting the hotseat applications at least 5
  times.
* custom_desktop: by default the desktop is fixed. The user can
  customize it only after starting at least 10 applications.
* multiple_desktop: by default there is only one single desktop.
  To get more desktop, the user needs to drop at least 3 items on
  the first one.
Added a simple analog clock widget