Removed old Kinect files (URDF, Xacro, mesh).
Added collada & texture for ASUS Xtion Pro Live.
Added Gazebo plugin for RGBD sensor
 - Mimics an OpenNI sensor e.g. Kinect/Xtion
 - Publishes MONO8 format "depth" image & PointCloud
 - Publishes RGB8 format color image & 2nd copy of PointCloud (for registered)
Added collision STL mesh from convex decomposition
Added file to store calibration values for sensors
Added xacro macro for ASUS Xtion Pro Live sensor
    - visual model, without base
    - collision geometry
    - TF frames
    - loads Gazebo plugin

    Note: There is a bug that Gazebo in ROS Fuerte ignores the roll/pitch/yaw in the visual tag,
          therefore it needs to be in a separate link, with the orientation specified at the joint.

    ToDo: Fix visual mesh, re-scale it, & the origin is not centered along the frontal axis.
          Can simplify collision mesh.
          Rotate origin in mesh, to match the orientation of the base link and bypass the bug.
Added REEM model with head-mounted ASUS Xtion.
Modified REEM launch with optional RGBD sensor.