[tlbuild] asy-2.63 build please

[Karl Berry]

John (Bowman) has released another version of asy, 2.63. This one is a
candidate for the TL release. (I thought the last one was, but what do I
know. :)

I've updated the sources and the support files are coming next. Please
commit new asy binaries or send me urls, as usual, when you have a chance.

Surprisingly, there no other changes to the sources as yet. --thanks, karl.