Initial import of an Eclipse JNI Project

This contains a small example for a JNI Method (tox_addfriend). I also added some base classes like an Exception type, and some enums that mirror the enums in the code.

Currently, it is not possible to build a jar from this, as it is incomplete, and I have not added that functionality to the Makefile yet. We will probably use a build system that is java-friendly like Ant or Maven, as they can both do JNI-Tasks to compile the libraries.