Fix a bunch of issues in vtimers

Not sure, might be better to wait for 0.9.5.  I don't have many games that use vtimers, but Wipeout Pure is happy with this change (although it wasn't without some other fixes.)

Was gonna squash these together a bit more, but am kinda tired, so I'm just gonna leave them.  They're not too spread out really.

Anyway, this fixes errors, return values, sceKernelUSec2SysClock, timing, etc.  I'm hopeful that it may help games that still have problems with vtimers still.  Also, I hope I did not break any Monster Hunter games (it doesn't seem like I did from the demos...)

Passes all the new vtimer tests.

-[Unknown]