[maven-release-plugin] prepare release presence-2.9.1

git-svn-id: https://source.sakaiproject.org/svn/presence/branches/presence-2.9.x@119679 66ffb92e-73f9-0310-93c1-f5514f145a0a
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://source.sakaiproject.org/svn/presence/branches/presence-2.9.x@119681 66ffb92e-73f9-0310-93c1-f5514f145a0a
Reverting pom back to SNAPSHOT

git-svn-id: https://source.sakaiproject.org/svn/presence/branches/presence-2.9.x@119715 66ffb92e-73f9-0310-93c1-f5514f145a0a