r4 release

[rctoris]

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