Fix compatibility with latest OGRE

In PointCloudRenderable::getWorldTransforms, call parent method
to obtain the world transform, as the name the matrix is stored in
has changed in newer versions. In RosLogListener, use updated signature
for Ogre::LogListener::messageLogged, if OGRE is newer than version
1.8.0.
Merge pull request #594 from spencerjackson/OGREFixes

Fix compatibility with latest OGRE