Use id instead of cid since cid changes each iteration

When using `model.cid`, every app was being re-rendered every time. Use
`id` since it stays the same across renders and fetches.
Document the health checks API options

* `initialDelaySeconds` is currently named `gracePeriodSeconds`
* `acceptableReponses` is not exposed in the API; it is hard-coded to
  [200 - 399]

Related to #305.
Make “health” “healthy” and wrap at 80 chars
Merge pull request #341 from mesosphere/document-health-checks

Document the health checks API options
Document default health check values

* `type` is currently `protocol` in master. Use the correct attribute
  name.
Clarify grace period is from task start
Prefer passing context to `map`
Align instance counts when not wrapped in pill

* Reuse `health-dot` class rather than duplicate CSS
* Switch unhealthy to `-error` to match Bootstrap naming scheme

Fixes #342.
Re-compile JS
Merge pull request #343 from mesosphere/align-instance-counts

Align instance counts
Move control of AppModal to root for routing

The next step is to let the Marathon app component do routing and render
modals or pages as needed.
moved build.properties to project folder
Merge pull request #346 from mesosphere/root-modal-control

Move control of AppModal to root for routing
Compile main JS with updated modal handling
Match line-height of AppList table with badge height

Badges made lines 28px tall rather than the default 20px. Increase the
line-height so text is aligned in the app table.
Re-enable destroy app with “#”

This was broken when the app modal was moved into the control of
Marathon.jsx. Re-enable the shortcut key.
Re-compile JS for fixed '#' delete shortcut key
Changes to front and back end to handle disk resources (as per #12).
Merge pull request #348 from mesosphere/handle-disk-resources

Changes to front and back end to handle disk resources (as per #12).
Remove `Content-Length` header for valid JSON response

Set content to `None` so the response does not set a `Content-Length`
header with value 0, which would tell clients to parse the body as JSON.
An empty string (response body with length 0) is invalid JSON.

Response before this change:

    HTTP/1.1 201 Created
    Location: http://localhost:8080/v2/apps/app-1234
    Content-Type: application/json
    Content-Length: 0
    Server: Jetty(8.y.z-SNAPSHOT)

Response after this change:

    HTTP/1.1 201 Created
    Location: http://localhost:8080/v2/apps/app-12345
    Content-Type: application/json
    Transfer-Encoding: chunked
    Server: Jetty(8.y.z-SNAPSHOT)

Fixes #349.