lib/jvm: include C header

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
lib/jvm: adds constructor to JavaVM

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
tests: add a test for the jvm module

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>