Update to newest parent version

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Switch from horribly non-shaded jruby-complete to saner dependencies

Especially in the Fiji project, we had tons of reports about problems
with woefully obsolete dependencies bundled in the jruby-complete.jar
file. So let's not use that one.

Should other dependencies be required, we can always add them back
later.

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