Fix some includes on Windows/etc.
Add ini options to configure the texture cache.
Fix #4922, kill age checks in texcache.
Cleanup differences in DirectX9 texcache code.
Add UI options for new texcache options.
Default off the texture cache options.

They cause noticeable glitches in a bunch of games.  The speed improvement
in some games is very good, but in quite a few it is small.