Merge pull request #120 from meyerj/fix-gazebo-plugins-segfaults

Segfaults in camera gazebo plugins due to uninitialized shared pointers
preparing for 2.3.3 release (catkin_generate_changelog, catkin_tag_changelog)
"2.3.3"
fix issue #38, gui segfault on model deletion by removing an obsolete call to set selected object state to "normal".