client-python

Merge pull request #11 from jekyc/custom_properties_and_observable_types

fixed conflict related to commit e1c3cc9f97e261014b36084ba7b8bbf0f89749da

Merge branch 'custom_properties_and_observable_types' of https://github.com/jekyc/client-python into custom_properties_and_observable_types

implemented/used new constants objects

initial creation of constaints.py file. This includes the identified constants and custom properties used internally be OpenCTI