This patch is for adding ip/htfilefs to Plan 9. Htfilefs does provide
the ability to mount a file lying on a HTTP server, like a ISO and fur-
ther use it on with other filesystems, like 9660srv. Behind it is a
simple caching mechanism, that downloads the requested blocks of 64K.
The default of blocks cache is 32 and is enough for being able to up-
date from a Plan 9 ISO that is lying on a HTTP server.