Fix cell server to work with updates to IPython

Works with commit b84b245b51a5b6d4e13a41ba79d773deaea59d63 on my branch.
make upstream directory if it doesn't exist
Merge branch 'master' of github.com:sagemath/sagecell
install requests; cleanup other things
expose all of require.js in the sagecell namespace
fix big bug in outputting stream text---it was only printing the first message.
Merge branch 'master' of github.com:sagemath/sagecell
Automatically mount iso when installing CentOS
Change loggng server to sage3
Merge branch 'master' of github.com:sagemath/sagecell
disable authentication for localhost VMs
make ssh options more consistent
Use the standard $LIBVIRT_DEFAULT_URI variable to give a default virsh session
update deployment scripts
put in old variable for virsh default connection
Add installation instructions from Davi dos Santos
Fix the auto-resizing to again resize between 3em and 14em, depending on content.

We had this working back in June.  For some reason, now all cells are sized to 14em.  This fixes the sizing issues so that they resize between 3 and 14em, depending on the content.
Add new deploy example
update iptables firewall rules to be a bit stricter, and reflect recent server changes
Update to work with the latest IPython widget branch

(IPython jdfreder/widget-msg commit 86eac83)