main: Fix the back icon in RTL
thumbnailer: Add support for rotated thumbnails

Similar to what we did in the movie player itself, but for thumbnails.
backend: Remove "show-cursor" property and API

It's now all handled within the widget.
backend: Fix hidden cursor with visible popup

Avoid the cursor being hidden when a popover menu is shown by forcing
the popup to be shown.

Reproducer:
1. Open Videos
2. Play a video
3. Move your cursor outside of the window
4. Wait until the hovering menu disappears
5. Open the gear popover without hovering the video
6. Hover the video

https://bugzilla.gnome.org/show_bug.cgi?id=730387
main: Use gtk_actionable_set_action_name()

Rather than setting the property by hand.
main: Move the "un-fullscreen" button to the corner

So that it's easier to reach when in fullscreen mode.

Requires:
https://git.gnome.org/browse/gnome-themes-standard/commit/themes/Adwaita/gtk-3.0?id=0f705f2097e44778eb665782f2cf23a889b2c73c

https://bugzilla.gnome.org/show_bug.cgi?id=727224
data: Fix man page compilation failure

GEN      org.gnome.totem.gschema.valid
totem-video-thumbnailer.pod around line 63: =over without closing =back
POD document had syntax errors at /usr/bin/pod2man line 69.
backend: Allow seeking past fill-level

When download buffering. This also improves download
buffering support by:
- Always doing the buffering query on the pipeline so that all
  elements can participate.
- Handling the GstCacheDownloadComplete message to know when
  download completed.
- Improving where we set the fill position try to find the fill
  level past our current playback position.

Based on patch by Bastien Nocera <hadess@hadess.net>

https://bugzilla.gnome.org/show_bug.cgi?id=635637
main: Fix crash when browsing Euronews source

In some locations, because the Euronews source would give out broken
URIs such as:
UNAVAILABLEUNAVAILABLE playpath=UNAVAILABLE swfVfy=1 swfUrl=http://euronews.com/media/player_live_1_14.swf live=1

https://bugzilla.gnome.org/show_bug.cgi?id=731224