Fixing include orders and whitelisting others.

Will be broken until clang SVN 253772 is available on travis/snapshots.

src/xenia/cpu/testing/sandbox_main.cc

@@ -8,8 +8,8 @@
  */
 
 #include "xenia/base/main.h"
-#include "xenia/cpu/cpu.h"
 #include "xenia/cpu/backend/x64/x64_backend.h"
+#include "xenia/cpu/cpu.h"
 #include "xenia/cpu/frontend/ppc_context.h"
 #include "xenia/cpu/frontend/ppc_frontend.h"
 #include "xenia/cpu/raw_module.h"