perf sched: Add 'perf sched latency' and 'perf sched replay'

Separate the option parsing cleanly and add two variants:

 - 'perf sched latency' (can be abbreviated via 'perf sched lat')
 - 'perf sched replay'  (can be abbreviated via 'perf sched rep')

Also add a repeat count option to replay and add a separation
set of options for replay.

Do the sorting setup only in the latency sub-command.

Display separate help screens for 'perf sched' and
'perf sched replay -h' - i.e. further separation of the
sub-commands.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>