Local debugger fixes and extensions

- Adds q/quit option to console debugging
- Adds options (variable_prefix)
- Breaks into debugger with Ctrl-C in local debug mode (Unix/Windows)
- Added option to list all breakpoints
- Fixes add/remove breakpoint bug (invalid path parsing)
- Minor cleanup

drivers/unix/os_unix.h

@@ -101,6 +101,7 @@ public:
 	virtual int get_processor_count() const;
 
 	virtual void debug_break();
+	virtual void initialize_debugging();
 
 	virtual String get_executable_path() const;
 	virtual String get_user_data_dir() const;