- added methods for setting background, border, node, and region color
- fixed flag.color, seat.which when colorizing with a variable
- fixed loading of the world map in spnet.example.basic
- improve graphic of spnet.example.basic
- minors fixes

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/spnet@25 edb9625f-4e0d-4859-8d74-9fd3b1da38cb