[Gtkradiant] some updates

[Timothee BESSET]

I've setup an amazon EC2 instance with MSVC Express 2008, and got
things setup to compile latest radiant trunk on win32 again.

Only major problem I hit was mhash, which is now more or less an
abandoned project and doesn't have win32 friendly stuff available for
download anymore. Since all we used was md4 and md5 hashing functions,
I removed that dependency and extended the md5lib module in the
Radiant tree to do what we need. The md4 implementation we use now is
from dovecot's public domain implementation.

I had to revert Rambetter's recent 335 and 336 checkins as they are
not compiling against the current set of precompiled dependencies
(http://zerowing.idsoftware.com/files/radiant/developer/1.6.1/). Those
changes are not lost, we should look at what exactly is a problem on
Windows, and maybe switch to a newer set of win32 gtk libraries, but
for now I feel it is more important to have all the platforms at a
basic working state.

The advantage of the EC2 instance is that once established the system
can be used as a shared resource for non windows developers to produce
binaries or verify their stuff. It can also be a reference for anyone
wanting to setup a windows build environment on their own hardware. If
anyone is interested in using the VM, let me know and I'll investigate
how to transfer a snapshot (you'll need an EC2 account obviously).

TTimo