SCons updates

* libraries are now generated in [BUILD_DIR]/lib
* passed the user_options to all libraries now.
  This means I could remove a couple of Export/Import lines.
* Changed the order in source/blender/src/SConscript and
  source/gameengine/SConscript.
  All libraries are now sorted alphabetically. This has no impact on the build
  process.

source/kernel/SConscript

@@ -4,6 +4,7 @@ kernel_env = Environment ()
 Import ('cflags')
 Import ('cxxflags')
 Import ('defines')
+Import ('user_options_dict')
 kernel_env.Append (CCFLAGS = cflags)
 kernel_env.Append (CXXFLAGS = cxxflags)
 kernel_env.Append (CPPDEFINES = defines)
@@ -19,4 +20,4 @@ kernel_env.Append (CPPPATH = ['gen_messaging',
                               '#/intern/string',
                               '#/intern/moto/include'])
 
-kernel_env.Library (target='#/lib/blender_kernel', source=source_files)
+kernel_env.Library (target='#'+user_options_dict['BUILD_DIR']+'/lib/blender_kernel', source=source_files)