Make the scheduler frequency tunable via ENV.
Fix a bug where the `disable` action did not work in SchedulerAgent.

Bad specs are fixed and specs that should be common among agents that
include AgentControllerConcern have been extracted to
spec/support/shared_examples/agent_controller_concern.rb.
Make `action` a mandatory option in preparation for making it interpolated.
Make `action` interpolated.
Merge branch 'fix-scheduler_agent'
Add CommanderAgent, which controls other agents on a schedule or incoming event.
Merge pull request #569 from knu/scheduler_frequency

Make the scheduler frequency tunable via ENV.
Merge pull request #570 from knu/commander_agent

Add CommanderAgent, which controls other agents on a schedule or incoming event.
Disable CSRF token verification in WebRequestsController.

This should suppress the "Can't verify CSRF token authenticity" warning.
`before_filter` is called `before_action` in Rails 4+.
Merge pull request #571 from knu/disable_csrf_warning

Disable the CSRF warning in WebRequestsController
Make action icons look clickable.
Rename icon_for_service() to omniauth_provider_icon().
Add omniauth_provider_name().
Use yes_no().
Add omniauth_button() and use some Sass tricks for DRY.
Alter the caption text format for services.

"(Twitter) knu" -> "Twitter: knu"
Show the service in Agent details page, styled as a label.
Set the button color for Tumblr.
Merge branch 'services_views'