JS: add manifest information for jar classpath to make it easier to run

Now the jar will carry classpath information so that it will use whatever version
of jogl2 is in the same directory.

Signed-off-by: Harvey Harrison <harvey.harrison@ausenco.com>
JS: add a build script for unix systems (path separator of classpath files)

Apparently javac takes differently formatted args for the classpath argument
depending what system it is run on, just provide a separate script for unix systems
rather than trying to smooth over the differences.

Signed-off-by: Harvey Harrison <harvey.harrison@ausenco.com>