Added missing variable declaration

This should fix the "reflow-bug" that produced the error message "compute_dimensions could not be found on undefined".
Merge pull request #4931 from weltraumpirat/master

Added missing variable declaration
Add radius text to first alert box

Having the radius on the first standard alert box without showing it in the code listing could be confusing for new users, especially since the second alert box doesn't have the radius.
Merge pull request #4935 from tracehelms/add-radius-text-to-first-kitchen-sink-alert

Add radius text to first alert box in kitchen sink
Merge branch 'master' of https://github.com/zurb/foundation
Added body class to indicate active clearing lightbox