Managed repository template path expansions

Refactors managed repository template path expansion to allow extra terms. Testing should be inspired by https://github.com/openmicroscopy/ome-documentation/pull/836 at http://www.openmicroscopy.org/site/support/omero5-staging/sysadmins/fs-upload-configuration.html. Try setting `omero.fs.repo.path` to various values then importing.
They're called via `Method.invoke` at the moment. That could easily be changed to a big else-if somewhere if need be. (Indeed, in JDK 7 we will be able to use strings in switch statements too!)