[Gtkradiant] initial merge of Alpha branch into trunk

[Timothee Besset]

Spent the last two days merging the content of Alpha into the trunk. CVS
did a lot of the work, and I tried to fix most of the broken stuff.
Comes to a point where I commited back what I had time to merge so far.
Some parts of the tree are compiling on linux (some of the modules) and
most of it is still broken. Didn't try compiling on win32 yet.

Now we enter a few weeks were we will finalize the merge. First, getting
everything to compile again, and then make it stable. I will spend the
next few days writing more documentation about the internals of 1.2, so
far it was mostly me and leo's thing, it greatly needs to be documented.

I will gladly accept patches to bring the current trunk towards
something functional. The trunk before the merge has been tagged
Pre-1_1-TA-Merge, so for any file in the tree, you should diff it
against it's Pre-1_1-TA-Merge version and against it's latest Alpha
branch version.

Most important issues right now are:
- win32: probably need to update some of the project files, I did all
the merging work on linux so far.
- compiling the editor core: on linux, editor core (i.e. radiant/) will
compile, and there is a bunch of unresolved appearing at link time. This
is mostly due to VFS changes and possibly some static libraries that are
no longer used on 1.2. I will spend some time describing the
dependencies between Editor components while fixing that part.

TTimo

PS: ViewCVS is a very handy tool to get diffs between arbitrary versions
of the code. Helps a lot during merge. See
http://zerowing.idsoftware.com/viewcvs/viewcvs.cgi/GtkRadiant/