removed ipxe submodule- we handle this with a checkout from within python

docs/TODO

@@ -2,6 +2,8 @@
 -i_am_a_racecar optimizations
 -see also: grep -HnR bdisk/*.py
 -TFTP, HTTP, RSYNC, git
+-UPDATE THE README!
+-sizes of build iso files
 
 ## General ##