trivial: Only show the package name when debugging fedora-tagger
Add header file so we can use __attribute__(cleanup) in future code
Support UNAVAILABLE desktop applications

These are applications we know about, but can't yet install.
Use an AsIcon internally to simplify a lot of complex code

This allows us to do three things:

 * Simplify the icon loading, and remove a lot of hacks and heuristics used.

 * Split out a plugin to download icons, which allows us to support remote icons
   for non-webapps which we'll use to good effect soon.

 * Simplify the epiphany web-app integration to avoid having two places to query
   application state.
Delay the updates-changed notification for a few seconds

This allows us to continue with the current multi-stage task without ripping
down and refreshing all the existing GsApp's.
Teach the PackageKit plugin to be able to install unavailable packages
Add UI to support unavailable packages