perf annotate: Add --demangle and --demangle-kernel

'perf annotate' supports --symbol but it's impossible to filter a C++
symbol. With --no-demangle one can filter easily by mangled function
name.

Signed-off-by: Martin Liška <mliska@suse.cz>
Link: http://lore.kernel.org/lkml/c3c7e959-9f7f-18e2-e795-f604275cbac3@suse.cz


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