[developers] Characterisation in MRS

[Ann Copestake]

I've just checked in revised code for the LKB - see separate msg to
developers - I'm afraid I have no clue about PET.  CFROM and CTO
should be in *ignored-sem-features* by the way - this ensures the MRS
code doesn't treat them as normal features.

> That sounds good. I reckon that for Pet we will just have  to add 
> another  -mrs=whatIwant  parameter
> to call the appropriate function, right?