Windows support

[mhss1]

• Fixed "source entry is not a Kotlin file" error when building on Windows
• Fixed TitleBar overlaps with the control buttons and not showing correctly on Windows (images below)
• Added Windows distribution configuration in build.gradle

"Build & Disassemble" was fixed by using File.pathSeparator instead of : and wrapping the classpath with qoutes.
"Run" was also fixed by using File.pathSeparator in the buildJavaCommand function

Title bar before

After

I wasn't sure who to include building the exe in the release.yml so I didn't edit it

[romainguy]

Thanks, much appreciated!