Hack to handle service discovery submodules correctly. This should maybe be changed in other interfaces.

Fix #525 / Fixes #525

* We should test if the command is in the path before trying to launch it
* Anyway, system is dirty, we should use dbus, at least for gnome-screensaver

* Endianness fix for RV15 and RV16 (mostly used for x11)

* RV32 works, I'm not sure of the masks for RV24 and RV16

    shifts.  Thanks to bigben for testing.

 with a vout (if only one is visible at the same time)
 A callback is now called when a layout becomes visible or hidden.
 The vout window is still not reparented correctly if the layout
 is changed while a video is being played...

 * shoutcast.c : remove "debug" printf

Change shoutcast service discovery module and write a new demux to be compatible with the new winamp 5.2 format. See trac ticket for detailed info. I'd appreciate if people could test this and proof read the code since we'll have to include this in 0.8.5 which is due to be released soon.

Ref #640.

debian/*: we no longer seems to requires gcc-snapshot. I commit mainly to test on the nightlies. feel free to revert.

- give myself some credit
- removed unnecessary PLUGIN_TO_HOST_GLUE macro