perf annotate browser: string search: /?n

perf annotate browser: string search: /?n

Using the same keystrokes as vim:

/ = search forward
n = search next forward/backwards
? = search backwards

Still needs to continue from start/end when not found, use HOME + / or
END + ? for now.

At some point we need a keybindings file to support ones favourite mode,
erm, like EMACS, etc.

Also we now need a 'h' window with all these keybindings.

Requested-by: Andi Kleen <andi@firstfloor.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-rv30xj2i258n0gwkzlu0c0bc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>