Fix inconsistent buffer sizes sent to analyzer

The analyzers are sent new buffers of audio data to process each time
they pass through the gst pipeline. Different file formats and bit depths/
sample rates can change the size of these buffers, in some cases making them
large and therefore infrequent. This causes choppiness in the analyzer
as it is not getting new data with every frame. This patch chunks the buffers
coming off the pipeline to correspond with the framerate of the analyzer.
Fix pointer arithmetic when seeking buffers

It's possible the sample type will change, so best to not use
a fixed value.
Synchronize buffer chunks with audio stream

The chunks are now determined by the density of data in the buffer
to the length of audio in the buffer. The chunk length can change
size so that the audio that is analysed is exactly what is being played
at the instant the frame is requested.
Fix oversized album cover art

When viewing the "Full Size" album covers, if the cover was higher in
resolution than that of the monitor, it would get cut off. Also,
the window was resizable however the image was not. This patch makes
the dialog a fixed size and resizes the cover only if it is too large to
fit on the screen. It also now displays the dimentions of the original
artwork in the title bar.
Refactoring
Apparently I'm blind. (Refactoring)
Merge pull request #4321 from TheUbuntuGuy/master

Fix inconsistent buffer sizes sent to analyzer
Add support for monitors in portrait mode

Album covers bound to width or height, whichever is smaller
Merge pull request #4327 from TheUbuntuGuy/coverchoicecontroller

Fix oversized album cover art.  Fixes #1260
Use a single label for the text at the top of the soundcloud settings page.
Merge pull request #4330 from paperbagcorner/soundcloudsettingslabel

Use a single label for the text at the top of the soundcloud settings page
Fix EOL for the second certifcate.
Use UNIX EOL, as for the first one.
Automatic merge of translations from Transifex (https://www.transifex.com/projects/p/clementine/resource/clementineplayer)
Only search for covers automatically if artist & album is filled.