Problem with custom IFileInfo implementation with FileSystemRazorProjectItem

[slavisharper]

Hi there,
I have small proposal for the FileSystemRazorProjectItem.cs.

Currently it is using FileInfo and not IFileInfo interface as input parameter. I've created custom RazorLightProject class that has
specific search terms for embedded resource files in multiple assemblies. The problem is that I'm using custom IFileInfo implementation and cannot create FileSystemRazorProjectItem.

For now I am using with TextSourceRazorProjectItem while testing this library, but I think that it will be better to be more abstract and use IFileInfo in the file class.