Some smallish updates

[d-Pixie]

Hi.

I'm not sure if you want updates in the official repo or if you'd rather people run with it. But the changes I made are really quite generic and you might like them. It's all in the commits ofc but here is the short list:

• Changed formatters to use call instead of format so one can use procs and lambdas as formatters.
• Removed use of global $; in favor of a Differ.separator class constant.
• Updated Readme to reflect that you can use regex as separator (including the difference between including a capture group and not).
• Removed rspec config block (since it was empty and used the deprecated syntax).
• Revamped the readme and converted it to markdown.

If you like it please merge. I will add some new features in the coming weeks and would be happy to restructure the code a bit more, if you want.

All the best!

[Nitrodist]

:shipit:

[tristantao]

:thumbsup: