Add glib-2.0 schema file

We're going to use the path: io.github.ikeydoherty.Budgie
Might look strange, but I don't own a domain name :)
Load media using directories in our media-dirs key

We'll add support in the UI for changing these directories soon.
If no value is set (first run) we'll set the keys to the music
and video special directories (xdg behaviour)
Add random and repeat settings schema
Track and store "random" and "repeat" settings
Replace highly inefficent time conversion utility.

Use div() from stdlib, on most machines this will perform division and
modulus in one operation, which is far more efficent than the previous
loop method.
Add time slider to PlayerStatusArea
Implement seeking

Important milestone on the road to v2, we can now seek back and forth
through media using the slider in our status area.
Do not allow seek slider to be focused
Begin adding path settings
Move Budgie settings into common.h

We need to access some of our settings from BudgieSettingsView, so it
makes no sense to keep our key names and schema defines inside of
BudgieWindow.
List current media-directories in Settings view (part 1)

This is part of issue #11, which requires a follow up commit to enable
configuration of those directories.
Fix bug for video playback started with settings open

If the playback moves to a video, and we've not yet realized the
drawing area, the playback will start in a new window if we're
in the settings view. This commit rectifies the issue by ensuring
the video area is always realized, ensuring the video will continue
to play in the background until the user hides the settings view.
Add schema note to README
Allow configuration of media directories (part 2)

This commit fixes #11, enabling the user to add or remove directories.
We don't handle cases (yet) where users remove all directories, because
its pretty unimportant. Budgie will always attempt to re-add the XDG
Music and Videos directory on start if no directories have been
configured.
Ensure we refresh media_dirs on reload
Bump to v2 (release pending)
Update screenshots for v2
Fix headers in BudgieDB files
Add new MediaQuery enum for upcoming search functions

Also decided to have a bit of a documenting session with budgie-db.h,
as this will eventually become a public header file
db: Add method to find all albums, artists, etc.

This will be used to help create the new browsing view, where it makes
more sense to know what albums we have, artists, etc, as opposed to
a spreadsheet view. (Yup, said it on Git.)