Bugfix release

The main reason for this release is a fix for issue #21, but under the hood there are also some changes to the way generators provide the form for their settings. This in preparation for more advanced use-cases in future releases.

What's Changed

• Form refactoring by @jeroen94704 in #20
• Fix labeltabs by @jeroen94704 in #19
• Fix issue #21 (missing geometry in light bin) by @jeroen94704 in #22

Full Changelog: v0.4.1...v0.4.2