nhc13 implementation limits

Runtime limits. There are various limits hard-coded into the runtime system, whose configured settings are:

node.h	max number of constructors in a data type	512
STABLE_ALLOCSIZE	max stable pointers (GreenCard)	1024
MAX_FILE_NAME	max length of filename for profiling	80
MAX_CDATA	max open files + ForeignObjs	1024
ARGSIZE	max commandline arguments	100
HEAPSIZE	default heap (change on commandline)	100000 words
STACKSIZE	default stack (change on commandline)	20000 words

The latest updates to these pages are available on the WWW from http://www.cs.york.ac.uk/fp/nhc13/