Cleanup responses mocking. Closes #1567

This unblocks requests to other websites with requests while Moto
is activated. It also adds a wildcard for AWS services to still
ensure no accidental requests are made for unmocked services

tests/test_core/test_request_mocking.py

@@ -0,0 +1,21 @@
+import requests
+import sure  # noqa
+
+import boto3
+from moto import mock_sqs
+
+
+@mock_sqs
+def test_passthrough_requests():
+    conn = boto3.client("sqs", region_name='us-west-1')
+    conn.create_queue(QueueName="queue1")
+
+    res = requests.get("https://httpbin.org/ip")
+    assert res.status_code == 200
+
+
+@mock_sqs
+def test_requests_to_amazon_subdomains_dont_work():
+    res = requests.get("https://fakeservice.amazonaws.com/foo/bar")
+    assert res.content == b"The method is not implemented"
+    assert res.status_code == 400