a bit of progress committed to send the code to another computer.
costmap_2d: array_parser.cpp compiles and tests work.
Still more to finish in costmap_2d_ros.cpp
Added support for footprint from rosparam.  Test currently crashing.
fixed crashing tests in costmap_2d
added tests and fixed bugs in loading of footprint from params
moved footprint ownership out of layers into LayeredCostmap
removed RobotFootprintManager class, not needed after previous changes.
Merge pull request #83 from ros-planning/fix-footprint-param

Fix for #63, backwards compatibility for footprint params