added patient entity, nhibernate & Sqlite

http://coding-journal.com/setting-up-nhibernate-with-sqlite-using-visual-studio-2010-and-nuget/
* make the nhibernate cfg and mapping files embedded resource with
correct assembly and namespace
* make entity class public
created dataaccess.cs with nhibernate db session creation in init()
called from app.xaml.cs satic sess object can be accessed from any where
dataaccess.sess