fix data file shipping confusions, force system compiling, correct libpath for pip

python-package/MANIFEST.in

@@ -5,3 +5,10 @@ recursive-include xgboost/windows *
 recursive-include xgboost/subtree *
 recursive-include xgboost/src *
 recursive-include xgboost/multi-node *
+#exclude pre-compiled .o file for less confusions
+#include the pre-compiled .so is needed as a placeholder
+#since it will be copy after compiling on the fly
+global-exclude xgboost/wrapper/*.so.gz
+global-exclude xgboost/*.o
+global-exclude *.pyo
+global-exclude *.pyc