[developers] minor LKB code changes

[Ann Copestake]

> Just a quick question: is  depth of rule application constrained at all, 
> then?

depth is controlled by *maximal-lex-rule-applications* in the UI but the 
problem is breadth is not (currently) controlled.  So the ERG has lots of 
punctuation rules that can apply and then others that can apply to the output, 
so with a value of *maximal-lex-rule-applications* which is high enough for 
the grammar to operate correctly, the number of outputs explodes.

I should perhaps make clear that *maximal-lex-rule-applications* is really 
only needed now for the case where a rule is being applied by the 
morphophonology and has no effect or where the base is longer than the affixed 
form and there are rule cycles.  Cyclically applicable non-morphological 
lexical rules are now controlled by the parser edge limit.   
*maximal-lex-rule-applications* is not really the right thing to use for 
controlling the UI since that needs to be analogous to the edge limit.

Ann