Ignore does not recognize the difference between rooted and non-rooted paths

[JKamsker]

Pr https://github.com/goelhardik/ignore/pull/43/files displays the error

[mitchcapper]

Further it likely should allow setting the root for comparisons. If I read a .gitignore in it would be useful to be able to set the root that file is found in. That way paths passed are first converted relative to that root.

IE if var ignore = new Ignore(Root="c:/Data/MyRepo"); and then called with ignore.IsIgnored("c:/Data/MyRepo/bob/first"); it should test /bob/first as the path.

This is pretty easy to do if you use System.IO.Path.GetRelativePath