initial commit of the fluid simulator.

Ton reviewed and gave his blessing.
Zr, can you have a look ?

see :
http://projects.blender.org/tracker/?func=detail&atid=127&aid=3039&group_id=9

for initial comments.

N_T : the solver itself (elbeem) needs some works to get rid of
warnings

tools/scons/bs/bs_libs.py

@@ -62,7 +62,8 @@ def blender_libs(env):
 		'blender_blenkernel',
 		'blender_LOD',
 		'blender_IK',
-		'blender_ONL'])
+		'blender_ONL',
+		'blender_elbeem' ])
 
 def ketsji_libs(env):
 	"""