Fixed #153 -- warn and return if no SSH keys found.
add timeout/attempts to util.connect_ssh, use 120s by default
raise EnvironmentError if no credentials provided
raise 400 on environment error, as in case of missing credentials
handle no credentials error on formation/node destroy
Fixed #124 -- fill in explicit values for Flavor params.
add uniqueness constraint on public key field, with migration and test
add 500.html template as part of api staticfiles
Fixed #144 -- check provisioning dependencies before running script
retry all chef api calls with configurable attempts and interval
Fixed #123 -- updated EC2 AMIs and pointers to them.
Added tests for Flavor updating.
Fixed #151 -- `deis flavors:update` working with tests.
Began work on #122 -- CLI-driven test suite.