Multiplatform setup

[RiccardoM]

Currently the project heavily depends on some methods that are available only on the JVM platform.

For example, we can see the usage of System.arrayCopy method used in a lot of places, as well as String.toCharArray and other JVM-only methods.

I think it would be great to set up the whole project to ne multiplatform ready, allowing us to delegate the implementation of such methods inside the proper JVM/JS/native modules.

The problem is: I don't know which organization would be the best. Having all those small modules, how should be proceed into this?

Working on this would make #61 easier

[ligi]

Unfortunately I do not yet have much experiences with multiplatform - and also currently not much time to dig into this. That said I would be happy if KEthereum gets multi-platform friendly. Ideally this is done by someone that uses KEthereum for multi-platform. I currently only use KEthereum for Android and console JVM projects.

[RiccardoM]

@ligi I think we should stop the development of new features until this issue is closed properly. Can we look at the PR and see if everything is fine/fix the remaining problems?