Bugfix; loading GUI file was only working when running tinbergen.py in its own directory.
Bugfix; loading GUI file was only working when running tinbergen.py in its own directory.

git-svn-id: 17f881b007ec480dbabdc95c576d5b303ba98edf@9 6e1c300f-f40b-46b6-bf97-71671448ae94

biogeo/tinbergen,biogeo/tinbergen