[Patch] mt_allocator: spare mem & fix alignment problems

[Benjamin Kosnik]

>Here is the nicest thing I can say: rope is one of those cool things
>that was never standardized.  The implementation we have was designed
>to work best with GC.  That is fine but we don't do GC in the library
>implementation.

Yes, this seems to be in-line with the consensus thinking on this issue.
Therefore, I'll not be trying to deprecate rope.

-benjamin