use builtin logging module
refactor to injecting nova client object

also misc cleanups, a few more tweaks to logging
Atwood theme
Had headnode twice in atwood
try to launch cluster without additional external files
missing slash
needs to be triple quoted
tweaks to startup without external files
tweak atwood theme
remove unnecessary ssh key generation on sully
remove dependency on M2Crypto and unused imports
schedule with maui

still somewhat preliminary, we should probably add the maui binaries to $PATH
and fall back on pbs_sched if building maui fails for some reason (the most likely thing
being that github is down).
tweaks to maui startup
the big refactor; make backend modular

This should enable support for cluster types besides just TORQUE.

A cluster object now handles the launching and specific types of
cluster implement methods to generate their launch scripts.
add atwood auth_url
bikeshed method name
make cloud determination more reliable
fix stupid typo
make startup resiliant to broken nodes
fix dumb bugs, make userscript work on headnode