Add Interceptor registration details to README.md
Retargeting to .NET 4
adding null check for DbCommandTreeInterceptionContext.DbContexts.  The collection can be empty under certain circumstances described here: http://entityframework.codeplex.com/wikipage?title=Interception
Merge branch 'patch-1'
adding null check for DbCommandTreeInterceptionContext.DbContexts.  The collection can be empty under certain circumstances described here: http://entityframework.codeplex.com/wikipage?title=Interception
Merge branch 'master' of https://github.com/dahrnsbrak/EntityFramework.Filters