Add the file types we say we support.  PHP and PY were mentioned, but not allowed.
(cherry picked from commit 8ec4ba95780716c30eee1a1e334bca66e20e561d)
Fix events config screen to allow selecting more than .sh

The File Manager and upload code handle putting files in the right
directories when they are uploaded, so there isn't a big reason to
filter the results in the events UI code as well, so just filter
out . and .. for now.
Playlist Editor fixes.

- Fix 'Event' type creation.
- Treat deprecated 'Video' type as 'Media' in the editor, which is
  what we do in fppd.  This rips out the rest of the Video type
  code
[Logs] Add git status and diff to data collected in log zip
[UI,Core] Add a developer.php page

This page is not available via the menus, but will allow developers or
users to switch branches.  It also shows the current 'git status' output.

When switching branches, binaries are recompiled.  Any compiled binaries
are cleaned up before switching.  Any compiled binaries which exactly
match the binary in git are removed.
[UI] Switch Git branch JavaScript to use jQuery for remote call
[UI] Fix typo in JavaScript
[UI] Switch manual git update to use jQuery for backend call
[UI] Tweaks to git pull and update code
Merge branch 'stage' into v0.3.0