Fix m3u export

This might not fix it, but it surely should eleviate the problem.
forwardport of [18324]

  - fspanel centering on right screen
  - fspanel don't hide if mousepointer is over fspanel

DISCLAIMER: libgcrypt includes various strong cryptographic ciphers.
VLC now has 256-bits ciphers, and already had 128-bits ciphers for some
time. Please check with your lawyer and country-specific homeland
security bureau. In France, *usage* is completely free. Supply, import
and export are not.

 - rationalize var_CreateGet*() and config_Get*() usage

...when the lower layer failed (ie TCP or SSL errors)

FIXME FIXME FIXME FIXME: EXPLICIT HACK.
On the one hand, we cannot hold the lock while triggering a callback, as
it causes a deadlock with video-on-top handling. On the other hand, we
have to lock while triggering the callback to:
 1/ make sure video-on-top remains in sync with fullscreen (i.e.
    unlocking creates a race condition if fullscreen is switched on and
    off VERY FAST).
 2/ avoid possible corruption bugs if another thread gets the mutex and
    modifies our data in-between (though it does not seem like it could really
    do much harm in this particular case).

This is obviously contradictory. Correct solutions may include:
 - putting the fullscreen NAND video-on-top logic out of libvlc,
   back into the video output plugins (ugly code duplication...),
 - serializing fullscreen and video-on-top handling properly instead of
   using the fullscreen callback. That's got to be the correct one.

It now checks if a capable "Media Player" is running, not only VLC.

TODO: playlist management

 activex: when linking against the shared lib DLL, it looks like the linker is picking the DLL name from inside the file, rather than the filename itself. in most cases, this is not a problem, as both are usually the same. Unfortunately, since libtool has a bug on cygwin, whereby the ouput name is libvlc.dll.exe rather than libvlc.dll, the wrong name 'libvlc.dll.exe' is used by the linker rather than the corrected filename. Using the import lib libvlc.dll.a instead fixes that problem. the proper fix should probably a patch to libtool