add io.pickler from ATLASOFF/PhysicsAnalysis/PyAnalysis/PyAnalysisUtils/trunk/python/root_pickle.py
PEP8
add pickler test
pickler docstrings
add a more complex io.pickler test and allow the dumping of pickles in directories
docstring
Merge pull request #353 from ndawe/pickle

io.pickler: pickle python data into a ROOT file, preserving references to ROOT objects.