Version-adaptive documentation

Concept

I am looking into the possibility of making certain pages of our Wiki be adaptive to the user's GNU Radio version (or desired version) so that sections which don't apply would be hidden. This would make cleaner page presentations and reduce the clutter of unrelated information.

Proof of Concept

Phase 1

 * Emulate MediaWiki with a local nodeJS program to allow non-destructive testing.
 * Create a test page with sections which can be hidden, based on 'data-*' attribute.
 * Create a form to enter Version info.
 * Store Version info in a user cookie.
 * Before displaying the page, execute a script to show or hide sections relevant to the Version info.