Use the new 16:9 screenshots
Add a loading icon to empty tiles

Show a content-loading icon while we are waiting for initial
content to appear.
Do not use the application state to modify how widgets are drawn

It's not nice to change the way the widget works using a special state value.
Instead of this, provide a method that only the updates panel will use and make
things less magic.
trivial: Never show the 'Update' button in the UI
Fix a few small memory leaks
trivial: Allow GsAppState to back to UNKNOWN from any state

We'll need this if we want to be clever and work around the state machine.
trivial: Fix up some internal method names
Always show 'Remove' in the details panel for updatable applications
Avoid reloading the overview more than once

Don't start another refresh if some of the pieces are still
loading. This can only lead to confusion.
trivial: Reduce the amount of debugging shown at startup
Do not show local applications without icons, names or comments
Remove the hardcoded screenshot plugin

It's not useful with a lot more data. AppStream will help us here in the future.
Do not install plugins just used in 'make check'
Support the Ubuntu extension 'X-AppInstall-Package' in desktop files
Add IBus frameworks installed by default as system apps
Remove the hardcoded ratings plugin

The data is very out of date and cannot be refreshed.