Add some robotics papers.

Adds three robotics papers:
* Adaptive Road Following using Self-Supervised Learning and Reverse Optical Flow - A neat paper from Stanford about how they were able to find desert roads during the DARPA Grand Challenge.
* DP-SLAM: Fast, Robust Simultaneous Localization and Mapping Without Predetermined Landmarks - A neat paper that uses particle filters for both the map and the robot's poses.
* RGB-D Mapping: Using Depth Cameras for Dense 3D Modeling of Indoor Environments - A paper that uses cameras that provide depth information (like the kinect) to build out 3D scenes and eventual localize & generate a map.