remove pointer to long conversions - part 1 of 3 (trunk only)

remove pointer to long conversions - part 1 of 3 (trunk only)

P64 (Win64) has a 64 bit pointer size, but a 32 bit long size.
Remove some code that forced pointers into a long int, and
vice versa where information could be lost.

This part deals with light source functions and their
arguments mostly, and switches some arguments
from type genericptr_t to 'anything'.