New methods "moveByXY" and "moveByBearing" have been added to Coords, addressing issue 39. Code cleanup and extensive documenting have been performed on Graphics and PNGIO, that now supports creating world file (optionnally). A new option has also been added to ARCIO, "A3D_view", to generate file names compatible with the Alpine3D's grid viewer (false by default). A new function to remove the extension from a file name has been implemented in IOUtils.