Refactor texture handling and fix rendering glitch.

BACKPORT
Fix sound glitch with "fade-out on pause" with GStreamer.

This is really just an ugly workaround for an issue with
(Phonon-)GStreamer. Essentially there is no way to flush the audio
buffers, so that implementing fade-out in combination with pausing
becomes a bit of a gamble.

Please test, as I cannot reproduce the sound glitch on my system!

BUG: 323729
FIXED-IN: 2.8.1
BACKPORT
OrganizeCollectionDialog: use promoted widgets instead of mixing .ui files with code

...preparation for a larger change.
The visualization now shows the effective volume during fade-out.

We now connect the visualization to the volume fader instead of
directly to the source, so that changes in volume caused by fading
out are actually visible.

BACKPORT
OrganizeCollectionDialog: hide complex options behind a button

In commit 7c780bf5, Ralf addressed bug 283361 by only showing the preview
table when the screen is large enough, which I believe went too far.

This is a bit different approach, the file scheme and other options are
hidden behind the Options button when the dialog is shown, making it much
more cleaner. The rationale is that the user usually sets up the options
once, not every time (and beginner users may be happy with the default
schema right away).

BUG: 327201
FIXED-IN: 2.9
Fix typo
OrganizeCollectionDialog: further improve usability

 * Remember dialog size
 * Make the preview sortable
 * Factor out common track paths of both preview and original to the
   header to save horizontal space
 * Prevent edits to the preview
 * Don't repaint the table when you only toggle overwrite mode
Remove QGLFunctions as it's only needed for OpenGL/ES and might crash.

BUG: 327150
FIXED-IN: 2.8.1
BACKPORT
Update radio stream URL.
SVN_SILENT made messages (.desktop file)
Fix for the abstract by Myriam Schweingruber
Add support for reading lyrics from tags.

REVIEW: 113389
Clean up the leftover of strigi removal

This is a follow up of commit 56ae345ad143a4101eebbe70f176a730c594e207

REVIEW: 114148
BUG: 328445
FIXED-IN: 2.9

Change wording in tool tip for more consistency
Make the scripts translatable through KDE translation system

REVIEW: 114282
CCBUG: 305264
FIXED-IN: 2.9
SVN_SILENT made messages (.desktop file)
SVN_SILENT made messages (.desktop file)
SVN_SILENT made messages (.desktop file)
SVN_SILENT made messages (.desktop file)
SVN_SILENT made messages (.desktop file)