perf report: Enable TUI in branch view mode

This patch updates perf report to support TUI mode
when the perf.data file contains samples with branch
stacks.

For each row in the report, it is possible to annotate
either the source or target of each branch.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1331246868-19905-5-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>