fix sometimes python cachelist problem
make python random seed invariant in each round
change rank order output to follow kaggle convention
ok
add rand seeds back
fix combine buffer
fix (trivial) leak in xgboost_regrank
Merge pull request #16 from smly/minor-leak

fix (trivial) leak in xgboost_regrank, Thanks for the fix
Update xgboost_regrank.h
Merge pull request #17 from tqchen/master

merge master fix into dev