Notify content observers when adding default podcasts.

* Podcasts show up in the podcast list as they are added, instead of
  needing to restart the program.
Minor code cleanups.
Delete and ignore local.properties.

* Shouldn't have been added to the repo -- for local paths.
* If $ANDROID_HOME is set, path to android sdk doesn't need to be set
  anyway.
Ignore the .gradle folder.
Add a context menu to the podcast list activity.

* Adds update and delete buttons.
Add the ability to update a feed/channel via the SyncAdapter mechanism.
Use a sync adapter to update channels.
Update AndroidManifest SDK to 14/19
Formatting a couple files.
[Fix] Bounds check after look up Url for a feed by id.
Request an channel sync after as the default podcasts are added.