Corrected missing polyfill resources -

* Excanvas and selectorvizr was missing from polyfill directory. Since yepnope has a 10000 millisecond resource timeout, this created a 20000 millisecond lag for all other tests and in Modernizr
* Corrects the lag noticed by @pjackson in PR #2978
* In addition removed selectorvizr from test suite since it is targeting only IE8 which is accommodated for in the conditionals of the HTML