Add net.imglib2.script.algorithm.integral package

This package (and related test code) arrived from the recently merged
albert-dev-fraction2 branch of the imglib2 core repository. See:

  https://github.com/imglib/imglib2/commit/73391e4fd4f346206fc8b4923664db148c67ef37
Fix package prefix of test classes

It should match the main artifact's net.imglib2.script package.
WIP: Update to the ImgLib2 stable release

This uses the pom-imglib2 parent to inherit common configuration blocks.
We no longer need to declare most versions, since they are managed.

This also renames the artifact to imglib2-script, for consistency with
its package prefix, and restarts the versioning at 0.1.0-SNAPSHOT.

It also makes the necessary code changes to adjust for the backwards
incompatibilities of the ImgLib2 release.

fixup! Update to the ImgLib2 2.0.1 release