* callback.h: Deleted, moved to ../include.

	* callback.h: Deleted, moved to ../include.
	* callback.c: Deleted, moved to ../sim/common.
	* Makefile.in (SFILES,COMMON_OBJS): Delete callback.[co].
	(callback.o): Delete rule.
	* remote-sim.h: No longer include callback.h
	(sim_callback_write_stdout): Delete prototype.
	* remote-sim.c (init_callbacks,end_callbacks): New functions.
	(gdb_os_write_stdout, gdb_os_printf_filtered): New functions.
	(gdb_callback, callbacks_initialized): New static globals.
	(gdbsim_open): Call init_callbacks.
	(gdbsim_close): Call end_callbacks.
	(simulator_command): Call init_callbacks.