Full EditorConfig parser with filesystem traversing, error reporting, and tests

- Defined class EditorConfig to parse and validate EditorConfig content.
- Added tests to check for correct values and extra options

No actual glob logic attached at present.

@devoncarew @gaurave 
I didn't use the `files` package, but I like the idea of using it.  If we do, I think it should be system-wide.  

I went ahead and traversed the filesystem in this pull request.  Probably was more work than should have gone into one PR, but it's done now.