Shader Disk Cache implementation for D3D. Saves generated shaders on disk. Eliminates "freeze jerks" in D3D plugin the _second_ and later times you play something.... not much to do about the first time. The D3D shader compiler is just slow.

Also assorted cleanup around the shader code.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@4869 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Core/Core/Src/PowerPC/Interpreter/Interpreter_FPUtils.h

@@ -232,8 +232,8 @@ inline u32 ConvertToSingle(u64 x)
 	}
 	else
 	{
-		// this is said to be undefined
-		// based on hardware tests
+		// This is said to be undefined.
+		// The code is based on hardware tests.
 		return ((x >> 32) & 0xc0000000) | ((x >> 29) & 0x3fffffff);
 	}
 }