chromium: Update dev channel to 25.0.1364.29.

For this update we needed to fix a bunch of things:

 * Limit pulse_audio_fix.patch to version 24 only (fixed upstream in 25).
 * Avoid the use of -fstack-protector for version 25.

The -fstack-protector option seems to be passed to libvpx now by default, so
simply use -fno-stack-protector in every occurence of -fstack-protector in
common.gypi. At least for now this will do it, but ultimately and for the future
we may want to have support for that in general.

And if we need that support in chromium directly depends on some of the next
updates to this package, as it seems that we now can switch to quite a lot of
nixpkgs dependencies instead of bundled dependencies.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
chromium: Update stable and beta to v24.0.1312.52.

The current beta version of chromium just became stable, which means that we are
now exactly in par with the beta channel.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
tkabber: Add ${tk}/bin to wrapper's PATH.

Pesky little impurity is now fixed, as it has bitten me several times in the
last days.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>