First pass at adding a jitter to schedulers. Move Validator to config_utils.
Update scheduler_parse interfaces to take a ConfigGenericSchedule.
Add jitter to constant scheduler, and some test cleanup.
Add jitter to general scheduler.
Update scheduler docs, Resolves #136
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.
Cleanup from code review.
Add docs about hourly alias for interval scheduler.
Merge branch 'release_0.6.1' of github.com:Yelp/Tron into 136_scheduler_jitter
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
Merge pull request #213 from dnephin/136_scheduler_jitter

scheduler jitter
Merge branch 'release_0.6.1' of github.com:Yelp/Tron into 0.6.1_command_client_interface

Conflicts:
	tron/api/adapter.py
	tron/api/www.py
	tron/core/actiongraph.py
	tron/node.py