Updated CSS Grid Layout support for Chrome

In June, 2013 (Chrome 29), Chrome enabled CSS Grid Layout support
Fixed a syntax error

Removed an extraneous comma.
Fixed a syntax error

Removed an extraneous state (no support), as the build does not accept multiple competing states (no support and polyfillable). Since polyfillable looks (in the website itself) like no support anyway, I only left that one.
Merge pull request #670 from phistuck/patch-4

Updated CSS Grid Layout support for Chrome