properly handle content_type callables returning a single internet media type as scalar

[amotl]

Improve and resolve #343, add appropriate tests.

[almet]

what is this? (should it be part of your .gitignore instead?)

[amotl]

• .idea is the project metadata folder of PyCharm, which is in pretty common use amongst our folks.
• When working with python virtualenvs, i think it is a convention to use .venv27 or .venv34 folders for designating the type of virtualenv. Given, when using tox one usually doesn't need manual-made virtualenvs for running the tests, but we usually even install tox into a project-local virtualenv to completely decouple from the system python.

Both entries shouldn't do any harm but instead should gain value for others, so they were added on purpose. However, we can remove them again if they make anyone sad.

[almet]

I believe these two lines should not be included because they're specific to one setup. It would make this file harder to maintain over time, for little benefit :-)

[almet]

Hi, and thanks for doing this! I've put a bunch of comments here and there, let me know when you had the time to address them!

[amotl]

Hey Alex, thanks for reviewing this. Will answer the comments inline.

[amotl]

Hi Alex, i tried to clarify my intentions and give an outlook. Let me know if there's still any blocking issue for you in this, otherwise i would appreciate doing a different PR for more cosmetic and cleanup work centered around the things mentioned. Best, Andreas.

[almet]

I think we're good once the .gitignore lines have been removed!

[amotl]

Thanks! The .gitignore lines have been removed by a squashed commit.

[almet]

Thanks!

[amotl]

Thanks for merging! Would you also have a look at #351? This complements this change as it improves and clarifies the documentation regarding this topic at the places @bomb-on and @leplatrem were looking at in the context of #343.