Ignore null, undefined, and NaN is dimension()
Add vjs.isNaN to have a better cross browser isNaN checker.
Previously, only undefined was ignored, so, it tried setting the
dimension using null and NaN as values. In most browsers this isn't a
problem, but in particular on IE8, things break.
With this PR, all three of those values will be ignored.
NaN & null should be treated as 0 in dimension()
When dimension() receives a NaN or null value for the number, it will
treat it as zero.
Updated tests to reflect that as well.
Merge branch 'the-N-Zone' of github.com:gkatsev/video.js into gkatsev-the-N-Zone
Added line to changelog for #1449