Cleanup sceKernelCreateVpl() and add warns/errors.
Always use -1 for failed allocs in block allocator.

Before it used 0 and -1, confusing.
Make sure BlockAllocator doesn't get off grain.

This should fix spurious warnings about AllocAt() when loading a game.
Implement basic waiting for VPL allocation.

Always times out so far, though.
Clean up sceKernelFreeVpl(), not waking yet.