Adds json parameter for POST requests
Adds review changes
Changes check on base and json. Fails on tests.
Fixes typo in test
Fix #2207

@Lukasa wrote the fix in #2207
Request->Response.
Merge pull request #2213 from kennethreitz/req-rsp

Request->Response.
Merge pull request #2210 from sigmavirus24/bug/2207

Fix #2207
requests v2.4.1
mils
lawl
Add more tests to `test_invalid_url`

This adds tests for the behavior introduced in b149be5d, where
`PreparedRequest` was made to skip `parse_url` for e.g.
`localhost:3128/`.
Merge pull request #2222 from blueyed/fix-MissingScheme-for-hostport

Add tests to test_invalid_url for `InvalidSchema`
Document skipping in PreparedRequest; followup to #2222
Merge pull request #2223 from blueyed/doc-followup-2222

Document skipping in PreparedRequest; followup to #2222
Added example of how to send multiple files in one request.
Moved multiple files upload example to advanced section.
Merge pull request #2227 from mjul/master

Added example of how to send multiple files in one request.
Fixup the remaining references to timeline.json.
Remove invoke from requirements.txt, docs