vlclua.c:  get rid of an empty module and fix descriptions

If someone wants to have it in there, it should probably rather be done
using a dedicated shortcut rather than a boolean configuration.

ptrdiff_t is signed so unequality comparison between pointers would
compute wrong when the two operands are within opposite halves of the
memory space.

Qt4 - Have a slider to control precisely the rate, usefull since we can here audio at all speeds now. :D
Patch by StFS - Stefán Freyr Stefánsson

Qt4 - Extended Panels: add callback on audio-presets to fix the issue when the audio menu does not match with extended settings.

example sout: '#transcode{acodec=wma1,samplerate=22050,ab=96,channels=2}\
:std{access=mmsh,mux=asfh,dst=:18080}'

XDG Base Directory Specification fix. I wasn't using the XDG_CACHE_HOME variable for the cache directory. Thanks to ILEoo for noticing.

whatever else might ever be invented

Change the QSettings stuff here too (this looks kind of hackish but at least it makes sure that we don't spawn multiple configuration folders)

Icons done by aLtgLasS.

Patch by Jean-François Massol

On OSes other than Windows, Mac OS X and BeOS (so it's Linux) comply with the XDG Base Directory Specification version 0.6. The old configuration file (vlcrc) will be copied to the new location. Other data like caches will have to be rebuilt (the album art cache in VLC was new in 0.9.0 so it's ok to lose it). Closes #1267