Add initial pom.xml

This is heavily based on Fiji's JNI_Example pom.xml, which in turn was
based off of https://github.com/imagej/minimal-ij1-plugin.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Use Fiji's JNI class to load the native library

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>