update modules doc to include default "importall Base.Operators"
other minor NEWS and doc updates
make Reverse immutable

I would kind of prefer to delete this since it doesn't really work.
some tiny flisp updates

pad symbol allocations to 8 bytes. malloc is probably doing this internally
anyway, but this makes valgrind happier.
found a gc_handle that looks like it should be made earlier. this probably
changes nothing, but couldn't hurt.