Allow calls to requsts between calls to responses.add

[Jlrine2]

This change allows the use of multiple responses intermixed by calls to requests by removing previous matches that have already been called if multiple exist.

[codecov]

Codecov Report

Merging #375 (aaf6838) into master (52e7484) will increase coverage by 0.11%.
The diff coverage is 100.00%.

❗ Current head aaf6838 differs from pull request most recent head bcf04d8. Consider uploading reports for the commit bcf04d8 to get more accurate results

@@            Coverage Diff             @@
##           master     #375      +/-   ##
==========================================
+ Coverage   96.51%   96.63%   +0.11%     
==========================================
  Files           3        3              
  Lines        1319     1365      +46     
==========================================
+ Hits         1273     1319      +46     
  Misses         46       46              

Impacted Files	Coverage Δ
responses/__init__.py	97.78% <100.00%> (+0.05%)	⬆️
responses/test_responses.py	98.21% <100.00%> (+0.07%)	⬆️

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[Jlrine2]

@markstory Is this good to go?

[markstory]

I think we might be missing some coverage on multiple responses. These changes cause the following test to fail, while it current passes on master.

def test_multiple_responses_out_of_order_two():
    @responses.activate
    def run():
        responses.add(responses.GET, "http://example.com", body="test")
        responses.add(responses.GET, "http://example.com", body="rest")
        responses.add(responses.GET, "http://example.com", body="fest")
        responses.add(responses.GET, "http://example.com", body="best")

        resp = requests.get("http://example.com")
        assert_response(resp, "test")

        resp = requests.get("http://example.com")
        assert_response(resp, "rest")

        resp = requests.get("http://example.com")
        assert_response(resp, "fest")

        resp = requests.get("http://example.com")
        assert_response(resp, "best")

        # After all responses are used, last response should be repeated
        resp = requests.get("http://example.com")
        assert_response(resp, "best")

    run()
    assert_reset()

[beliaev-maksim]

@markstory
we can close current PR as #455 is merged