appcompat v7 (aka action bars for old devices)

NOTE: This bumps the minSdkVersion from 5 to 7, which means we no longer support Android 1.6

Alrighty, now all Activities extend ActionBarActivity. This means that they will have ActionBar's, but also they support adding Fragments to their layout. This allows for more complex UI's in the future. The patch changes every single activity, not just those wanting to change their UI in the future, because if we have have UI's which rely on ActionBar's, then it would be odd to have some activities using the new UI and some the old when on a gingerbread device.

NOTE: This has broken the ant and eclipse build systems, so don't feel obliged to merge it just yet. I added it as a MR because I'm rebasing off it, and thought it might be useful. Also, other people may be able to help at some point, but I will revisit the build system in the near future. I started work on the ant build, and got it almost completely working, but failed at one one of the last steps (packaging the .apk file). The way I got it working, was to add a -pre-build task in custom_rules.xml, which copies all of the resources from the appcompat-v7 submodule into the bin/res dir, so that they get included in the build process. Although this works in the compilation stages, it doesn't work in the packaging stage for some reason. Secondly, I've used the same -pre-build task to copy the libs/support-v4.jar file to the preferencefragment submodule as it is a required dependency. The gradle build deals with this more elagently, and in the future, the ant build should copy this jar from the appcompat-v4 submodule, but that is a story for another day.