add some more tests
update data uri used to detect webp to be one of newest webp format, also crank the "persist support" localStorage key
Add exclusion of Android 4 native browser, but not Chrome, using negative lookahead in regex
note origin of our 1x1 webp graphic
Adding build file
Rebuilding
Merge pull request #168 from mobify/v2.0-webp-moar-ua-tests

Better webp detection
Fixes an issue in Android 2.3 where JSON.parse-ing `null` throws an exception.
Merge pull request #169 from mobify/v2.0-fix-android2.3

Fixes an issue in Android 2.3 where JSON.parse-ing `null` throws an exception
Merge branch 'v2.0' into v2.0-picturefill

Conflicts:
	tests/resizeImages.html
Updating README.md