It was being indirectly included, causing VS to syntactically mark std::min/max usages as being undefined (however it still compiled fine, of course)

Various fixes to formatting and whitespace

We only support rgba32 for a while now, so there is no need to have everything in common configureable.

For a long time, we've had ugly and inconsistent function names here as
helpers, names like "decodebytesRGB5A3rgba" which are absolutely
incomprehensible to understand. Fix this by introducing a new consistent
naming scheme, where the above function now becomes "DecodeBytes_RGB5A3".

Instead of having three separate functions and checking the tlutfmt in a
variety of places, just do it once in a helper method. This is already
for the slow path either in our Generic decoder or in our Software
renderer, so it doesn't matter that this is slower.

x64 will continue using the separate functions for speed.

This removes the requirement for the TextureDecoder to have access to
global texture memory.

Quick code cleanup. The enum names and values come from libogc.