Replaced occurrences of 'wb-nav' with 'wb-info'.
Merge pull request #3842 from thomasgohard/wb-nav-to-wb-info

Replaced occurrences of 'wb-nav' with 'wb-info'
MathML: added Modernizr.mathml test
MathML: added test to check if polyfill should load

The `complete` handler cleans up the Modernizr.mathml test elements.
This handler should be removed once the bug has been fixed in Modernizr.
MathML: added JEP polyfill and working examples