Dark mode for Ignition 8.3 Designer

Dark mode now works inside Vision, and I'm looking for Vision developers to test it.

In the previous version the module switched itself off as soon as you opened a Vision window, because a window saved from a dark Designer picked up classes a Vision client cannot load. Since the latest version that is fixed at the serialiser. Please use version 0.4.1. If you have bugs post it here or create a github issue.

One known limitation: the Vision canvas renders in dark colours in the Designer wherever components use the look-and-feel defaults; the client is always light. Nothing is written into the window by that.