Make JHOVE less dependent on JAVA (as an external dependency)

[RvanVeenendaal]

As briefly discussed in person with Carl today.
JHOVE depends on JAVA.
When I installed Fedora Linux on a laptop, I think it came with a 'headless' JAVA install.
JHOVE raised an error when I tried to start it with that JAVA version, so I changed my JAVA install to a 'normal' version.
Also, on systems without JAVA, JHOVE won't work.
It might be an idea to (also) provide a JHOVE version with JAVA included (cf. DROID).