Support for Kotlin, Java, JVM

This is our first official release of Astronomy Engine that includes support for Kotlin and Java for the JVM. There are also a few minor enhancements and improvements in the other supported languages.

Special thanks to: @ebraminio, who helped me get the build environment set up, taught me lots of cool stuff about the Kotlin language, and provided numerous code reviews and extremely helpful feedback the whole time. His help made this project much faster and greatly improved the quality of the work.