Changed modifiers of extract function.

Added call to `distinct` on activity type stream.

Merge pull request #1 from AaronCoplan/unirest-version

Updated Activity related methods to use better error handling.

Updated Comment related methods to use better error handling.

Updated Label related methods to use better error handling.

Updated Task related methods to use better error handling.

Updated error handling for all project related functions.

Improving error handling.

Upgraded dependency version.

Added fields to ExtraData.

Added ability to fetch activity for projects.

Deleted unused RequestExecutor.

Finalized ability to get activity and filter by type(s).

Adding Activity data model.