Remove freefuncs.c, which hasn't been used in a long time and is not

worth the effort to continue to maintain.  Since freeObject() is not
capable of coping with cases like multiple links to a node, it's
unlikely that it ever will be useful again.  We now have memory
context management that offers a faster and more reliable way of
getting rid of arbitrary node trees (at the cost of having to know
in advance of building the tree that you'll want to get rid of it).