{tree}:save & {tree}:restore

[Guido.Bosch@loria.fr (Guido Bosch)]

I could need some lower-level functions for saving and restoring trees
in polish format {tree}:save and {tree}:restore are much too unwieldy
for my needs: The first one needs a complete file name, but adds a
".po" suffix, the second one expects a file name and a search path. 

I just want 

	{tree}:my-save :    TREE FILE -> BOOLEAN 
	{tree}:my-restore : FILE      -> TREE

where FILE is a complete file name with directory and file name. No
assumptions about suffixes, library paths and the like should be done.
	
	Guido