Nice delay slots, ahoy

This takes a conservative approach to enabling nice delay slots:

 * Moved FPU/VFPU/ALU checks to separate functions to be safe.
 * Whitelisted common ops (based on profiling) in delay slots with correct info flags.
 * Added a define to quickly disable nice delay slots in debugging.
 * Should apply well to ARM as well.

There may be a better way to do the op whitelist (than string compare), but since it's only on compile time I think it shouldn't be expensive.  The most common is noop for sure.

Should reduce memory reads/writes, both from no need for pushf/popf/savedPC and from less regcache flushing.

-[Unknown]