EditorconfigParsing: mixed attribution

https://github.com/coala/coala-quickstart/commits/master/coala_quickstart/info_extractors/EditorconfigParsing.py contains PSF licensed code, which may be acceptable in a AGPL project.

However there are at least two serious problems with this:

1. it has only one commit with both upstream code and local modifications. Thus it is not possible to see which code was authored by @satwikkansal and which code is copyright to other authors. Any PSF licensed code in an AGPL project must comply with AGPL terms.
2. it does not show who were the authors of the other code. There is a link to another GitHub project, where metadata could be manually found, however licensing compliance should not rely on the existence of some other stuff on the internet, which may disappear. GitHub repos do disappear infrequently.

The mixing of attribution in a single commit is a licensing problem, at least for AGPL, as 'contributors' have rights, so it must be possible to determine who the right holders are.

The second problem is easy to solve by explicitly listing the usernames or names/emails of the authors of the relevant content at the time it was forked without history being retained.

The easiest way to resolve this may be to submit all changes upstream, thus making all code changes unambiguously PSF-licensed and attribution clear, and then update the header of the file to link to the upstream PR. (this does somewhat still leave licensing compliance reliant on other stuff on the internet, however the importance difference is that then our local file is an exact copy of the code in the upstream PR, so the entire licensing issue is deferred to another project)

Alternatives include:

- documenting the specific lines which were added vs forked,
- deleting the file and re-adding it as two or more commits with correct metadata
- splitting the file into two files of different origins (copied vs local modifications).