Blender Git Loki

SCons updates
* Game engine can now be build on Linux. By default this feature is disabled.
The reason is that you need to have a precompiled version of the ode library
for your gcc version.
To enable ode support you need to do the following:
- compile ode.
- set BUILD_GAMEENGINE = 'true' in the config.opts file.
- set USE_PHYSICS='ode' in the config.opts file.
- set the ODE_INCLUDE and ODE_LIBPATH to valid locations.

* Linking order has changed for the game engine
There are cyclic dependencies between libraries. On linux we have to do some
duplicate linking. I looked at the order of linking in source/Makefile, and
did some clean up.