perf c2c report: Add support to manage symbol name length

The width of symbol and source line entries could get really long
and not convenient to display. Adding support to display only
patrt of such strings and possibility to switch to full length
by uing --full-symbols option or 's' key in TUI browser.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-yxf5hfteyfaoi8xrgczqtyha@git.kernel.org


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