Adding better register tracking through locals and fixing branches.

LLVM does an amazing job of optimizing this. There are many opportunities
to make it better, too, by preventing spilling where not required or only
spilling/filling things when needed.

include/xenia/cpu/ppc/state.h

@@ -40,6 +40,10 @@
 // }  // FPRF
 
 
+#define kXEPPCRegLR     0xFFFF0001
+#define kXEPPCRegCTR    0xFFFF0002
+
+
 typedef struct XECACHEALIGN xe_float4 {
   union {
     struct {