CSS optimization updated to remove unnecessary whitespace.

Optimisation while still keeping line breaks is not really optimising, it leaves leading & trailing whitespace and other kinds of whitespace that safely can be removed. This pull request makes it possible to optimise css files more efficiently.

The default option has been updated to make sure the default output does not change with this pull request.
Documentation might need to be updated to mention which version this will be included in. If provided the version number, I'll amend this pr.

I have signed and submitted the Dojo Foundation CLA.