unicode-chars.srfi

Now that my laptop's working properly again, I was going to resync my
integration branch with Tom's latest changes.  (star-merge resulted in
having duplicate tags in my tree, but I just deleted srfis in the root
of the tree and it seems okay now)

In unicode-chars.srfi, however, I noticed it's been updated to include
the syntax "\U(xxxx)", but the syntax I'd recommended earlier on the
mailing list was "\(U+xxxx)" -- intentional or typo?

(Assuming intentional, the lexer already supports the latter, so I'll
have to fix it to support the former if that's what you want to use
instead.  Also, what about buckybits?)

-jivera