Move trace file writer out of tracepoint.c

Move trace file writer out of tracepoint.c

This patch is a refactor which moves trace file writer related code
out of tracepoint.c, which has 6k LOC.  It moves general trace file
writer to a new file tracefile.c and moves tfile specific writer to
tracefile-tfile.c.

gdb:

2014-02-23  Yao Qi  <yao@codesourcery.com>

	* Makefile.in (REMOTE_OBS): Append tracefile.o and
	tracefile-tfile.o.
	(HFILES_NO_SRCDIR): Add tracefile.h.
	* ctf.c: Include "tracefile.h".
	* tracefile.h: New file.
	* tracefile.c: New file
	* tracefile-tfile.c: New file.
	* tracepoint.c: Include "tracefile.h".
	(free_uploaded_tps, free_uploaded_tsvs): Remove declarations.
	(stop_reason_names): Add const.
	(trace_file_writer_xfree): Move it to tracefile.c.
	(trace_save, trace_save_command, trace_save_tfile): Likewise.
	(trace_save_ctf): Likewise.
	(struct tfile_trace_file_writer): Move it to tracefile-tfile.c.
	(tfile_target_save, tfile_dtor, tfile_start): Likewise.
	(tfile_write_header, tfile_write_regblock_type): Likewise.
	(tfile_write_status, tfile_write_uploaded_tsv): Likewise.
	(tfile_write_uploaded_tp, tfile_write_definition_end): Likewise.
	(tfile_write_raw_data, tfile_end): Likewise.
	(tfile_trace_file_writer_new): Likewise.
	(free_uploaded_tp): Make it extern.
	(free_uploaded_tsv): Make it extern.
	(_initialize_tracepoint): Move code to register command 'tsave'
	to tracefile.c.
	* tracepoint.h (stop_reason_names): Declare.
	(struct trace_frame_write_ops): Move it to tracefile.h.
	(struct trace_file_write_ops): Likewise.
	(struct trace_file_writer): Likewise.
	(free_uploaded_tsvs, free_uploaded_tps): Declare.