Added get_ticker_history and tests to client library. (#319)

* Added get_events and tests to client library.

RV1:
- added get_events function to client library
- added tests.

RV2:
- changed get_ticker_events to get_ticker_history

RV3:
- changed history to events and modifed classes to meet new requirements.

* run make rest-spec

Co-authored-by: danielatpolygonio <[email protected]>

Author: antdjohns