Requests-mock

Bug Fix on 1.9.0 release:

* Added py.typed file required to make type annotations work.

A number of small improvements:

* Feature: Adds type hints for python 3. 94
* Fixes Bug: Handle whitespace encoding in URL. 158
* Fixes Bug: Allow subclassing the mocker object. 160

Solidifies the behaviour of nested mocking and the real_http variable.

Releasing a few pull-requests that people will find useful.

Includes fixes for 93 and 106. These should be inconsequential for most people.