r4 release

 * Initial pose now set in SceneNode [(rctoris)](https://github.com/rctoris/)
 * Texture method for OccupancyGrid changed to canvas to allow for very large maps [(rctoris)](https://github.com/rctoris/)
 * OccupancyGrid origin now in corner instead of center of image [(rctoris)](https://github.com/rctoris/)
 * Optional TF client added to occupancy grid client [(rctoris)](https://github.com/rctoris/)
 * Interactive markers now removed correctly [(rctoris)](https://github.com/rctoris/)
 * Viewer now takes an optional initial camera position [(rctoris)](https://github.com/rctoris/)
 * Orbit controls fixed to prevent flicker during camera pan [(rctoris)](https://github.com/rctoris/)
 * Scale (units) now work in Collada files [(rctoris)](https://github.com/rctoris/)
 * Grunt files added and code cleanup for linter [(rctoris)](https://github.com/rctoris/)