gazebo_plugins: fix linkedit issues

Note: other linkedit errors were fixed upstream
in gazebo
gazebo_plugins: replace deprecated boost function

This is related to this gazebo issue:

https://bitbucket.org/osrf/gazebo/issue/581/boost-shared_-_cast-are-deprecated-removed
gazebo_ros: fixed missing dependency on TinyXML
Merge pull request #100 from ros-simulation/fix_osx

Fixes found while building on OS X
Merge pull request #97 from bit-pirate/hydro-devel

gazebo_ros_openni_kinect plugin: adds publishing of the camera info again (fixes #95)
enable image generation when pointcloud is requested, as the generated image is used by the pointcloud
Merge branch 'hydro-devel' of https://github.com/ros-simulation/gazebo_ros_pkgs into hydro-devel
Merge branch 'hydro-devel' into hydro-devel-openni-fixed