Feature Request: Add Gradle Support

[JJTech0130]

Would it be possible to configure this repo with gradle, such that one monolithic repository can build both the production code and the simulator with different targets? I don’t have time to invest in this, but it seems possible and would be a very nice feature to have.

[jkenney2]

Agreed. I've made a couple of attempts with both gradle and maven. I have no experience with those systems, and kept running into errors. Learning about them is on my to-do list. I'll leave this issue open.

[JJTech0130]

I'm working on it, but Java modules are a headache. I might just stick to Java 8 for now and see if that solves it...
[EDIT]: So, I've go a problem: Jamepad doesn't support modules (williamahartman/Jamepad#22), and JavaFX failing mysteriously because the javafx.controllers is not visible, and I can't make it visible without making Jamepad not work because of aforementioned non-support for modules. I'm probably just doing this wrong, but I can't figure out what...
For reference, this is the error I'm getting:

> Task :run FAILED
Error occurred during initialization of boot layer
java.lang.module.FindException: Module javafx.controls not found