Add stylish rules to root of project

[jappeace]

It maybe convenient for others to apply formatting like this as well. I just ran:

stylish-haskell --defaults > .stylish-haskell.yaml

and then modified that align clause.

[qrilka]

I'll try to look into it this weekend, won't we need modules reformatted to conform to this style?

[jappeace]

Good point, I'm not sure how to get the same style without a ruleset like this. I'll try tinkering with the options tomorrow to see if I can get the same one. I hoped it'd just be the default one with the align modified

[qrilka]

I think having a fixed styling for the library is a good thing so I'm OK with merging this. I guess README could have section saying that we'd advise to follow this styling on new commits while older modules could have some non-conforming styling in place. Could you add that? And I guess in the same merge we could also switch README's extension to the more widely used extension .md

[jappeace]

@qrilka I believe I've added it as you asked.

[qrilka]

Thank you