AUI-1364 - Make aui-toggler accessible

Hi Marc,

Attached is an update for https://issues.liferay.com/browse/AUI-1364.

For this one I had to use almost the same code in aui-toggler and aui-toggler-delegate.  I tried to find another way but it's strange because aui-toggler-delegate uses aui-toggler but does not extend it.  Do you think there is a better way to approach this?

Also, I fixed an issue in the toggler demo with some css classes being initially set incorrectly causing some funky behavior.

Please let me know if there are any issues.

Thanks!