Changes
* GUI Icons are much more responsive when colors change. They very rarely get "stuck" on the wrong color/brightness
* Spaced out rectangle selection pairs to make it more obvious which 2 are grouped
* Removed a _ton_ of copy-paste code, which should make fixing future bugs a lot simpler.
Notes
* This is hopefully the last pre-release before Official 1.6.0
* No need to manually delete your `config.ini`; the app now automatically does this if it's out of date.