skel: exclude unneeded freehep/aida dependencies

The freehep maven repository pulls in a number of dependencies which are not necessary for our runtime requirements.

After trial-and-error twiddling, I have determined that the following constitute the minimal set:

freehep-application-2.0.3.jar
freehep-graphics2d-2.2.1.jar
freehep-graphicsbase-2.2.1.jar
freehep-graphicsio-2.2.1.jar
freehep-io-2.2.2.jar
freehep-jaida-3.4.1.jar
freehep-swing-2.0.6.jar
freehep-util-2.0.5.jar
aida-3.3.1.jar
aida-dev-3.3.jar
jel-2.0.1.jar
openide-lookup-1.9-patched-1.0.jar

Hence the pom.xml has been modified to exclude those that are safe to eliminate.  Note that direct dependencies only is not an option as freehep-jaida-3.4.1.jar is needed, but carries many of the other unnecessary dependencies with it.

Testing:

Excluded subsidiary dependencies then added them back in until plots were generated without error.

Target: master
Request: 2.6
Patch: http://rb.dcache.org/r/6117
Require-notes: no
Require-book: no
Acked-by: Gerd