Implementing and Using Repositories with NHibernate in C#

This is an example of utilizing the Repository pattern in C# implemented with NHibernate as data access framework but keeping in mind to provide a layer of abstraction to easy switch to another data access provider (Entity Framework for example). Patterns like Approval, Finder, Persistor, etc. Connecting to SQLite in memory; SQLite in file; Postgres with FluentNHibernate.