[theEvilReaper]

Proposed changes

The pull request addresses the following issues:

• GamePhase#removeListener now removes the listener that is actually registered, and returns null instead of throwing an NPE for unknown event classes
• Calling GamePhase#start on a phase that is already running no longer fails with "Node already has a parent"
• TimedPhase#onFinish is only invoked once, even if finish() is called multiple times
• Resuming a paused LinearPhaseSeries no longer skips the running phase, and pausing before the series has started no longer throws

Types of changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of
them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before
merging your code.

• I have read the CONTRIBUTING.md
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[github-actions]

Test results

 81 files   81 suites   17s ⏱️
116 tests 116 ✅ 0 💤 0 ❌
348 runs  348 ✅ 0 💤 0 ❌

Results for commit c71e73e.