*Removed an occurance of former angle item in gtk.

*Fixed a bug in ES management introduced lately in DVD/DvdRead.

*Beginning of reorganisation in DVD plugin source files, in order to try to
make it easier to understand. There is some work left though :p.

*Decreased the score for VCD plugin, as the VCD demuxer was used even
for DVD :p. It should make autodetection work.
Some comment:
-I think that VCDInit should make a test on the access plugin and be launched
only if the access plugin is VCD,
-VCDOpen shouldn't set p_input->b_error: if it fails we just try another
module,
-PSRead doesn't need to be duplicated anymore: input_ReadPS is now available
for plugins (cf Christophe's commit).

Please comment around that: I'd like to know if the behaviour I've described
is the one everyone expects.

Enjoy my new bugs :p