It accumulates CPU and Memory usage for the allocation as a whole as well
as by task.

It follows the form of poll -> json parse -> append,
Where append is defined in subclasses to add data from the new frame
to long-lived rolling arrays of data.

The maxLength is enforced by removing elements from the head of the
list.

Add a -race enabled build to Travis

* 'master' of https://github.com/hashicorp/nomad: (59 commits)
  Test coverage for the promote canary feature
  Update README.md
  launcher readme
  Add stats to launcher
  Add stats to example plugin
  Example device plugin and helpers
  Fix the flickering issue with start/stop job
  Add a confirmation loading state to the two-step-button component
  Switch stop/run job actions to EC tasks
  Test coverage for the Start Job behavior
  Add Start Job action on the job overview page for when a job is dead
  gofmt -s
  Update the info message about token storage
  Switch token storage to localStorage from sessionStorage
  add stats to device interface
  Change the latest deployment component to include a Promote Canary button
  Support the promote deployment api action
  Simplify the data control flow around job.plan()
  statistics protos
  Acceptance tests for the edit behaviors on the job definition page
  ...

UI: Job Writes

UI: Restart stopped job

UI: Promote canary

UI: Use localStorage instead of sessionStorage to store ACL tokens

Example device plugin and helpers

This PR introduces:
* An example device plugin that exposes files as devices for testing.
* Helpers for serving a device plugin
* A launcher binary that allows interacting with a device plugin without
needing a Nomad client.

Device plugins expose device statistics

When the server doesn't respond immediately, there is a visible window
of time between the action being submitted and the blocking query coming
back with the new job status.

UI: Edit a job

Allow it to fail for now with the goal of making it the default build in
the future.

Add documentation for eligibility toggle endpoint

Rebased docs reorg