Maven dependency names

This is a branch started by @chris-allan to rationalize the ivy configurations in the OMERO build. One of the primary goals of this is to allow building maven and gradle projects easily from http://artifacts.openmicroscopy.org.

The state of the branch is now this:
 * POMs are generated for all of the build artifacts, as well as `-sources` and `-javadoc` jars. They are not *yet* being pushed anywhere; that is likely to be taken care of by Jenkins.
 * DEV versions are no longer named `-DEV-ice35` but simply `SNAPSHOT`. This will require some further discussion:
   * Do we have a snapshot repo per ice version?
   * Do we rework all version numbers to have `ice` *before* `SNAPSHOT`?
   * Also, they're named `4.4.$PREVIOUS-SNAPSHOT` as opposed to `4.4.$NEXT-SNAPSHOT` which is likely to be an issue.
 * All the `<dependency/>` orgs, names, and versions are now rationalized. This required a few work-arounds beyond just ivy changes which could be considered "breaking":
   * Bump jamon from 2.7 to 2.75 (now downloaded)
   * Bump xml-apis from 1.3.02 to 1.3.04 (now downloaded)
   * Lower-case PDFBox and FontBox
   * Drop `Java50` from backport-concurrent-utils name
   * The `target/repository` directory now has a new layout (m2-style).
 * The downloaded jars should now be saved to `~/.m2` while built jars should be left in `lib/cache` for later deleting.
 * There are a few FIXMEs & and TODOs which need to be handled before this can be merged.

At the moment, none of the release jars are in the repository and so getting this to work takes a local adjustment. But roughly:
 * Build with this branch as usual (`./build.py`).
 * Check the new artifacts in `target/repository`.
 * Clone https://github.com/joshmoore/pom-omero-client and run `mvn install`
 * Clone http://github.com/joshmoore/minimal-omero-client and:
   * Configure `pom.xml` to point at your just built `target/repository` directory.
   * Run `mvn install` **or** import the project with m2eclipse.

/cc @ctrueden @chris-allan @bpindelski @jburel @dominikl @mtbc