Update README.md

Minor spelling correction. useage -> usage
Merge pull request #25 from wykhuh/master

Update README.md
Removed css fallbacks

Centred classes are not compatible with current release (centred
classes require extra container div)
Corrected version
Update for 1.1.1
Correct resize start/stop test
Avoid divide by 0 bug

Thanks @g-van-vreckem
Merge pull request #36 from jonom/master

Update to match master