(Baxter) Depth Sensor MoveIt! updates for Indigo

- Added Xtion depth sensor support (using openni_launch)
- Updated the Kinect launch dependency from openni to freenect for indigo
- Added rgb and depth frame parameters to remove leading '/' that tf2
  warned about in the console
- (aside) Updated the gitignore to ignore the warehouse directory that is auto-generated
This is meant to be an example placement transform, and modified by the end user (same as the kinect transform was before). However, we have a community member who has created a 3D-printable chest mount that works quite well with the Xtion. So instead of 1 meter in front of the robot, I have more or less approximated the static transform for that mount, to give users a point to start. What is your vision with setting a rosparam?

Here's the link to that 3D printable mount:  http://robotics.cs.uml.edu/baxter-solar-plextion/
It seems like uml's robotics website is down today though. I managed to download the mounting file before, so I'll host it on the Rethink wiki and post here.