Add “About” modal that displays /v2/info data

* The endpoint is polled when the modal is opened and then not again
* Modal can be opened with “shift+,” (to mimic OS X’s command+, for
  opening app preferences)
Remove padding-bottom on nav for border-bottom

Removing padding-top pulled the text up rather than keep it in place.
Add keyboard shortcuts to move to “apps” and “deployments”

* “g a”: go to apps
* “g d”: go to deployments
Remove console statement, strictly
Add JSHint exceptions, strictify
Allow undefined in ObjectDlComp since data is async
Color `<code>` to blend with `<dl>`
Use h5 to match app modal headers
Specify padding-top as required by app modal

Fixing change made in commit
5080b3680955ea90c79fb4f9ccbc237e5fb8de05.
Converge on “Unspecified” term
Err… fix “Unspecified” node
Wrap JSON output in `<code>`

Because… it’s code.
Remove unused “blink” keyframe animation
Invert docs/about link

* Give the Docs link an external-looking arrow to show it goes off site
Add whitespace and “constant” unspecified node

Per feedback.
Wrap modal to multiple lines, one line is too long
fixes a flaky test
Added default value for task version
Merge pull request #615 from mesosphere/task-version-default

Added default value for task version
Setting version to 0.7.0-RC4