v0.4.0

Refactor of CEs internals.
Now each Builder has it's own Configuration record which is used throughout the creation of the Widget.
Only at the end the widget is actually created instead of modifying the existing Widget step by step.
This was a necessary refactor because the methods previously used may have some undesirable effects on the final Widget created.

Full Changelog: v0.3.1...v0.4.0