[developers] coreference problem fixed

[Bernd Kiefer]

Hi Emily,

i think i fixed the problem that leads to different readings for LKB and
PET with the grammar you gave Peter. He tracked the problem down and i
could verify with a small example grammar that it now seems to work.

On my way to solution, i unfortunately found another bug concerning
coreferences in type definitions which obviously nobody found yet.

TDL allows definitions of the following form:

foo := [ f0 #co1 & #co2 & [ a 1 ],
	f1 #co1,
	f2 #co2 ].

but this results in the following structure after flop'ing it:

[ f0 #c1 [ a 1 ], f1 #c1, f2 *top* ]

Obviously, the second coref is not treated properly. I think this error 
is hard to track down if used in a grammar, thus i wanted to warn you,
just in case.

Best,
	Bernd