perf timechart: Add backtrace support

Add -g flag to `perf timechart record` which saves callchain info in the
perf.data.

When generating SVG, add backtrace information to the figure details, so
now it's possible to see which code path woke up the task and why some
task went to sleep.

Signed-off-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1383323151-19810-8-git-send-email-stfomichev@yandex-team.ru


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>