Adding new 'perf data' command to provide operations over data files.

The 'perf data convert' sub command is coming in following patch, but
there's possibility for other useful commands like 'perf data ls' (to
display perf data file in directory in ls style).
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremie Galarneau <jgalar@efficios.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1424470628-5969-3-git-send-email-jolsa@kernel.orgSigned-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>