Kernel: Made SyncRequest not pure virtual, with a default implementation of error (as this is not required for all kernel objects)

- SVC: Added ExitThread support
- SVC: Added SignalEvent support
- Thread: Added WAITTYPE_EVENT for waiting threads for event signals
- Thread: Added support for blocking on other threads to finish (e.g. Thread::Join)
- Thread: Added debug function for printing current threads ready for execution
- Thread: Removed hack/broken thread ready state code from Kernel::Reschedule
- Mutex: Moved WaitCurrentThread from SVC to Mutex::WaitSynchronization
- Event: Added support for blocking threads on event signalling

Kernel: Added missing algorithm #include for use of std::find on non-Windows platforms.

hle: added a hokey way to force a thread reschedule during CPU single step mode (as used by the debugger)

arm: fixed a bug where ARM_Interpreter::ExecuteInstructions was actually executing one more instruction than expected

kernel: changed main thread priority to default, updated Kernel::Reschedule to use PrepareReschedule

svc: updated waitSychronization to not overwrite handle on return, added stub for SleepThread (does nothing)

thread: updated Reschedule to sit at a synchronization barrier when no other threads are ready for execution

event: added a hackish ability to set an event as "locked" to its current state, cleaned up some comments

- force kernel reschedule after svcWaitSynchronization
- fixed some bugs with passing in pointer arguments
- cleaned up some comments and log messages