First pass at Gstreamer 1.0 porting.

This at least compiles against gstreamer 1.2.
Things that work:
* Playing audio
* Automatically completing tags

Things that don't work
* Spotify
* Moodbar

Things I haven't tested
* Transcoding
Merge branch 'master' into gstreamer-1.2
Merge branch 'master' into gstreamer-1.2

Conflicts:
	ext/clementine-spotifyblob/mediapipeline.cpp
	gst/moodbar/gstfftwspectrum.c
	src/core/songloader.cpp
	src/core/songloader.h
	src/engines/gstengine.cpp
	src/engines/gstenginepipeline.cpp
	src/moodbar/moodbarpipeline.cpp
	src/musicbrainz/chromaprinter.cpp
	src/transcoder/transcoder.cpp
	src/ui/mainwindow.cpp
	src/visualisations/projectmvisualisation.cpp
Rewrite moodbar stuff for gstreamer-1.0:
- Rewrite gstspectrum (1.0) to use FFTW (2x faster) and emit raw magnitude
  values (not log scaled).
- Rewrite the moodbar generation code to be somewhat understandable, and
  do it in Clementine instead of gstreamer.
Various bits for gstreamer-1.0 compatability
Don't crash if we can't write to the moodbar cache
Merge branch 'master' into gstreamer-1.2

Conflicts:
	src/moodbar/moodbarloader.cpp
Make Spotify work with gstreamer-1.0.
Fix misleading offset_bytes names
Remove useless check
Automatic merge of translations from Transifex (https://www.transifex.com/projects/p/clementine/resource/clementineplayer)
Name chromaprint's config.h chromaprint_config.h so QtCreator doesn't get confused.
gstreamer-cdda is in gst-plugins-base in 1.0 and has a different header name.

This still doesn't work because the API has changed and track listings are
now delivered via a bus message instead of direct access to the struct's
members.
Change the deb and rpm specs to use gstreamer-1.0 instead of 0.10
Disable AUDIOCD by default - it's broken in gstreamer-1.0 because of API
changes.
Merge branch 'gstreamer-1.2'

Fixes #3332
Merge branch 'master' of github.com:clementine-player/Clementine
Fix Spotify Blob installation promt. Fixes  #4538.
Add the ability to add a Spotify track to a Spotify playlist through context menu.
TODO: drag and drop (i.e. implement DropMimeData), update special playlist (Favorites), remove from playlist.
Merge branch 'master' of github.com:clementine-player/Clementine