Use OrangeExtensions instead of Apple ones

The OrangeExtensions are a pluggable jar containing stubs for the Apple
Java Extensions, updated for Java 5 & 6. They are kept more up to date
than the official Apple ones, and also are available on Central.

For details, see:
https://ymasory.github.io/OrangeExtensions/

Thanks to @gab1one for the idea:
https://github.com/knime-ip/knip-scijava-bundles/issues/4