build91 additions

[Christopher Blizzard]

build91 is up for download in the usual place:

http://olpc.download.redhat.com/olpc/streams/development/build91/

New stuff includes:

* New kernel that includes support for QEMU networking (and probably a 
good number of other fixes)
* ltrace and strace have been added to the devel packages
* New packages libXcomposite and libXdamage, both needed by marco and 
dan for sugar
* X config is done during the first startup and should work on both QEMU 
and the boards

Light testing here shows that it works on both the board from a USB key 
and inside of QEMU under FC6-test4.

--Chris