Modification of gr-trellis to support multiple initial and/o

Hello All,

I would like to modify the Viterbi algorithm to support multiple
initial and final states.

For example if I have a FSM with 5 states {0,1,2,3,4} I would like to
pass a subset of the states as the initial and/or final states, for
example S0 = {0,2,3} and SK = {3,4}.

I think the logical way to do this is to pass the initial states S0
and the final states as vectors. I think the modification in the
Viterbi algorithm is straight forward; a small modification to where
the initial alpha value is set and where the final state is selected
prior to traceback.

If this sounds like a good idea to everyone I will make the
modifications and submit a patch.

If anyone thinks I should do this a different way please let me know.