renamed LinkingModel in ChaingraphModel to be more consistent with the ChaingraphMOdelBuilder
added WeightType and weight_map to ChaingraphModel
added build to gitignore
python pickle support for TraxelStore
linking boost_serialization into libpgmlink to make it easier to link against pgmlink
setup a learning_systemtest stub
energy functions are now feature functions; cleaned up legacy interface of energy/featue functions