* gdbtk.c (gdbtk_flush gdbtk_fputs): Buffer up output to make

	* gdbtk.c (gdbtk_flush gdbtk_fputs):  Buffer up output to make
	disassembly more efficient.
	* (breakpoint_notify):  Include pc in gdbtk_tcl_breakpoint
	callback.
	* (gdb_loc):  Include pc in return value.  Also, return function
	name if arg was specified.
	* (gdb_cmd_stub):  Call gdb_flush to drain internal GDB buffers
	after command completes.
	* (gdbtk_init):  Improve error handling.

	* gdbtk.tcl:  Add lots of comments.  Clean up code.
	* (gdbtk_tcl_fputs):  Make output window redirectable.
	* Add assembly window, and breapoint support.
	* Make button 1 in margin toggle breakpoints.
	* Use stippling to indicate breakpoint disabling.