Make modal larger with togglable tabs
Print config with multiple values on multiple lines
Stringify container object as JSON for display

* A stringified JSON object is a decent format for displaying container
  information since it can potentially contain many options.
* Prefer "Unspecified" for values not specified when creating an App.
  "None" can be misleading since there are likely environment variables
  and a default executor, which is different than "None".
Merge pull request #143 from mesosphere/modal-large

Large App modal with all configuration options