Add more modules for compatibility layer.

scikits/learn/ball_tree.py

+import warnings
+warnings.warn('scikits.learn namespace is deprecated, please use sklearn instead')
+from sklearn.ball_tree import *

scikits/learn/lda.py

+import warnings
+warnings.warn('scikits.learn namespace is deprecated, please use sklearn instead')
+from sklearn.lda import *

scikits/learn/metrics/__init__.py

+import warnings
+warnings.warn('scikits.learn is deprecated, please use sklearn')
+from sklearn.metrics import *

scikits/learn/mixture/__init__.py

+import warnings
+warnings.warn('scikits.learn is deprecated, please use sklearn')
+from sklearn.mixture import *

scikits/learn/naive_bayes.py

+import warnings
+warnings.warn('scikits.learn namespace is deprecated, please use sklearn instead')
+from sklearn.naive_bayes import *

scikits/learn/neighbors.py

+import warnings
+warnings.warn('scikits.learn namespace is deprecated, please use sklearn instead')
+from sklearn.neighbors import *

scikits/learn/pipeline.py

+import warnings
+warnings.warn('scikits.learn namespace is deprecated, please use sklearn instead')
+from sklearn.pipeline import *

scikits/learn/qda.py

+import warnings
+warnings.warn('scikits.learn namespace is deprecated, please use sklearn instead')
+from sklearn.pda import *