Fix kotlin engine

[hanslovsky]

This PR fixes the Kotlin scripting engine and re-implements in Kotlin while at it. The major issues were

1. The Kotlin script engine is not thread-safe and would be in an unrecoverable state after failure. Fixed by wrapping in an engine that synchronizes all calls.
2. The Kotlin script engine does not use bindings in a useful way. Fixed by updating Kotlin version. Required a few changes to pom.xml.

Status:

• Tests run successfully in IntelliJ
• Tests run successfully on command line: StackOverflow, Kotlin Discourse
• Installed into Fiji.app/jars and confirmed that it worked: imklib

[hanslovsky]

I was able to get the unit tests to work on the command line. The issue was the surefire plugin that would use a manifest-only jar that would contain the classpath. For some reason, the order in which the jars were listed in that manifest-only jar caused the issues described in the Kotlin Discourse linked in the initial PR comment. I was able to fix this issue by setting

<properties>
	<surefire.useManifestOnlyJar>false</surefire.useManifestOnlyJar>
</properties>

For more details on that surefire property, see

mvn surefire:help -Ddetail=true

[ctrueden]

Thanks a lot, @hanslovsky! 🍻