Clean up  sceKernelWaitThreadEnd() wrappers.
Make sceKernelWaitThreadEnd return the exit status.

Also fix the exit status not being recorded properly.
Properly set thread status on create/term/start.
Implement timeouts for sceKernelWaitThreadEnd().
Correct error codes for sceKernelWaitThreadEnd().
Add warnings to sceKernelCreateThread().

Trying to check when it's being misused.
Avoid calling thread->getName() in release builds.

Profile shows this will save a couple percentage points.
Implement sceKernelReleaseWaitThread().
Merge pull request #361 from unknownbrackets/thread-funcs

sceKernelWaitThreadEnd(), ...ReleaseFromWait(), and warnings