Add switch between STAGING and RELEASE repositories

The Sonatype STAGING and RELEASE repositories are now auto-selected
depending on whether the version number has a STAGING or RELEASE suffix.
Remove unused bzip2 library

Osmosis used to depend on an Apache bzip2 library that was not available
on Maven Central (part of Ant I think ...).  This has been replaced by
the commons-compress library so the old library can now be deleted from
the Osmosis repository.