Correct opacity problems on Chrome when disabled, fix switchChange triggering

I've bundled up a few necessary fixes committed by others into a pull request.

There is a pretty obvious problem with the visualization of the switch on Chrome, when it is disabled, indeterminate or readonly, which is fixed by the MAEDA nobuhiro commits.

The frapontillo commits fix some problems triggering switchChange when updating multiple switches.

Finally, I've rebuilt the css and js.