thread: removed unused SwitchContext/Reschedule reason field, added missing arg parameter to SVC CreateThread
thread: renamed "WaitCurThread" to "WaitCurrentThread", removed unused "reason" argument
lcd: added thread wait after (faked) vblank interrupt (would have) occurred
svc: added a check to ensure that a service was implemented before attempting to connect to its port
core: added Kernel::Reschedule() call to check for thread changes, shortened delay time to 100 instructions