Add sceKernelWaitSignal and sceKernelSendSignal (#462)
Add sceKernelWaitSignal and sceKernelSendSignal (#462)

* Add sceKernelWaitSignal and sceKernelSendSignal

* Update threadmgr.h

* Update threadmgr.h
vitasdk/vita-headers,Rinnegatamante/vita-headers,Rinnegatamante/vita-headers,Rinnegatamante/vita-headers,Rinnegatamante/vita-headers,vitasdk/vita-headers,vitasdk/vita-headers,vitasdk/vita-headers