Add more ssh_options for configuring timeouts, and jitter settings.
Adding docs for new ssh options config.
Rename restart_interval to restart_delay, update docs, and add deprecation warning.
Improve error message for config parsing of command context strings.
Resolves #173, view job runs using negative index.
Replace many instances of Turtle.
Merge pull request #219 from dnephin/0.6.1_node_configuration_options

Move some ssh option constants to the config
Merge pull request #220 from dnephin/173_negative_numbers_for_job_run

negative numbers for job run
Merge branch 'release_0.6.1' of github.com:Yelp/Tron into 136_scheduler_jitter
Merge branch '136_scheduler_jitter' of github.com:dnephin/Tron into 136_scheduler_jitter