Add `/.editorconfig`

## See: http://editorconfig.org/
> > SUPER annoying for windows users.
> 
> What @SBoudrias is referring to is that, by forcing `LF`, Windows users will get something like: 
> 
> ```text
> line▯line▯line▯line▯line▯
> ```

Only in a crappy editor. :+1: to enforcing LF as the default.