DashClock extension that shows the number of updates.

This is nicer than a notification, and I have strived to make it look aesthetically pleasing on DashClock.
Use Case: Friendly reminder for someone who likes to flash nighly builds as soon as they are uploaded.

Change-Id: I28facad38442c0e8d0b6fb0a70b71b340430e408
Clean up CMUpdater.

Remove a lot of legacy code (e.g. remainders of incremental ROM support)
and get rid of weird design patterns, such as spawning another process
to get a system property value.

Also make the update check service a little more clever:
- it's now able to be cancelled
- it doesn't fetch changelogs that are later dropped anymore

Change-Id: I07b16a0c3bb55791b0025698ede2c9e0f4e969de
Merge branch 'cm-10.1' of github.com:CyanogenMod/android_packages_apps_CMUpdater into cm-10.1