Modify pom.xml for OSGi-capable deployments

This patch does two things:

* adds the Apache Felix Bundle plugin to the pom file which will generate the
  appropriate OSGi headers;
* change the packaging type from 'jar' to 'bundle' to enable the bundle plugin to
  join the build.

'bundle' is the same process as 'jar' with the extra step of scanning the
classes and generating the OSGi headers into META-INF/MANIFEST.MF.  The only
difference between 'bundle' and 'jar' are the extra headers in the manifest.

[fge: modify commit message]