A new debugger.

Lots of bugs/rough edges/etc - issues will be filed.
Old-style debugging still works (just use --emit_source_annotations to get
the helpful movs back and --break_on_instruction will still fire).

src/xenia/kernel/xthread.h

@@ -161,6 +161,7 @@ class XThread : public XObject {
   uint32_t active_cpu() const;
   void SetActiveCpu(uint32_t cpu_index);
 
+  uint32_t suspend_count();
   X_STATUS Resume(uint32_t* out_suspend_count = nullptr);
   X_STATUS Suspend(uint32_t* out_suspend_count);
   X_STATUS Delay(uint32_t processor_mode, uint32_t alertable,