Revert "Added class to subclass speaklater._LazyString and enable Flask JSON serialization."
Revert "Added class to subclass speaklater._LazyString and enable Flask JSON serialization."

This reverts commit dde1dff84266a0fd7e75c45d3daad70136c53296.

TkTech/flask-babel,mitsuhiko/flask-babel,mitsuhiko/flask-babel