Remove bad param from sceKernelPollEventFlag().

Not that it was necessarily hurting anything...
Stop warning on invalid sempahores.

They've been helpful, but it's finally been a while since it's mattered.
Don't warn for umd0: and ms0:, not problems.
Fix sceKernelCreateMsgPipe() and alloc psp memory.

Might not matter, but I'm not sure yet if it's expoesd somewhere.
Cleanup some minor usage in msgpipes.
Return better results from msgpipe waits.

Not fully tested, but it's clearer to specify.  Delete and cancel are sure
to have been wrong.
Clean up cancel and delete for msgpipes.
Don't even try to allocate a 0 sized buffer.
Implement basic timeouts for msg pipes.
Verify msgpipe threads are waiting before waking.
Start out with 0 written msgpipe bytes.
Don't wait on a msgpipe when timeout <= 2.
Wrap the msgpipe send functions.
Sort msgpipe waits while waking (like others.)
Simplify and fix msgpipe send queuing logic.

Should reschedule, should wait in line, couple error messages.
When sorting, also clear not waiting threads.
Fix send of 0 bytes, more error handling.
Fix a weird sceKernelTrySendMsgPipe() edge case.
Wrap sceKernelReceiveMsgPipe() and friends.
Add some error checking to msgpipe receives.