Changes

tmf.ui: add support for unicode character marker symbols

This is very useful to be able to identify markers by letters
or more importantly by numbers to show sequences.

Change-Id: I99044e1166e9c6835c35a4903b618e03781ca712
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Signed-off-by: Christophe Bedard <bedard.christophe@gmail.com>