* fix for first time use xgboost tree plotting. The path is not correctly added to system.
0.1.8
* bug fix in plotting xgboost * docstrings improved
0.1.7
* gradientboosting added to trees * small fixes * new examples added
0.1.6
* graphviz files removed from package and linked to external source * graphviz files are only downloaded when windows is used * small fixes regarding plots * Should work under Unix too mow