Cleaned up less, sass, and scss to use .transition mixins

Updating less, sass and scss mixins to use the `.transition()` mixin on the `.waves-notransition` class.

Previous pull request didn't compile under the node less package.

Note to make a mixin important in less, adding `!important` outside the mixin will make *all* lines generated by the mixin important (eg. `.transition(none) !important;`). Sadly we can't pass `!important` into mixins.