Merge pull request #13 from EducationalTestingService/develop

Adding simple unit tests and new function to parse already tagged sentences and files.
Merge pull request #14 from EducationalTestingService/develop

Added functions to parse tagged data into the server.
Adding examples of parsing tagged data into `zpar_client.py`
Merge branch 'hotfix/zpar_client_fix'
Merge branch 'master' into develop