Premake: Changed to use PCH when compiling tests.
CxxTest: Got rid of /Wp64 warnings. Changed TS_ASSERT_STR_EQUALS to
print both strings on failure.
win_internal: Added the bits that CxxTest::Win32Gui needs (because
Win32Gui is now compiled with PCH and uses our sysdep headers).
Disabled test_cache_policies, because it took long enough for me to read
its name.
This was SVN commit r4237.