#371 - Specs for groups, pipelines, instances, stages done.
#371 - Specs for operations and pause messages.
#371 - Split latest stage name and state.
#371 - Handle previous instance blurb.
#371 - Add some comments in the new dashboard JSON ERB.
#371 - Small refactor - dashboard JSON erb - around pause operation.
#371 - Change: .to_json() => .to_json
#371 - Make temporary changes needed to make new JSON work.

* New JSON can now be accessed at: http://SERVER:8153/go/pipelines.new_json
pipeline history api
agent job run history api
job history api
stage history api
handle empty data in api models
config api: material listing
to_json not required during json rendering
#371 - Now accessible as dashboard.json

* Removed temporary .new_json mime type alias.
Merge remote-tracking branch 'origin/master' into new_dashboard_json
config api: revision listing
config api: diff b/w 2 commits
pipeline status api