Continuing the march toward EC2 compatibility

src/LaunchSweep.py
    username for ssh/scp to new VM should be ubuntu, not ec2-user
src/Nube.py
    use new VM's internal IP not external IP (now that we are
    no longer testing from a notebook)
src/README
    refresh
src/SweepServer.py
    replace hard-coded m1.tiny with m1.small (yikes!)
src/sweep.config
    use EC2 sample data instead of CESWP OpenStack
src/sweepserver
    tweak directories & port
test/launchSweep.py
    insignificant tweaks for amazon environment