[Gtkradiant] changes in trunk

[Timothee Besset]

I merged in the recent changes from the Alpha branch / 1.1 into the trunk. 
Mostly the mod support code and the other improvements we've made since the 
initial Alpha -> trunk merge. Have a look to docs/developer/CHANGES if you 
want more details and check the viewcvs
http://zerowing.idsoftware.com/viewcvs/viewcvs.cgi/GtkRadiant/

Status update otherwise:

Next Q3 PR is looking good, so I should have more time on Radiant once Q3 
1.30 is out. We will probably have another stable release of 1.1-TA (which 
we will call 1.1-TA.1 I guess), with recent fixes and some media updates 
(shader scripts, .def files positions).
Otherwise work on 1.2 should continue. There is a lot of new code from Spog 
that waits to be patched in, and some fixes should go in the trunk to make 
it more stable. The immediate priority is to get the .map module 
functional, so that we could throw in .xmap quickly (.xmap == XML map format)

TTimo