delegate Func defined without namespace

[andrensairr]

I had an issue attempting to use the .NET's default System.Func definition. Even when using System;, and having no references to dbqf namespaces, writing Func<MyType, bool> predicate; always refers to the dbqf type because this delegate is defined in the global namespace. Not a huge issue, but it does result in unnecessarily fully qualified variable types when the System.Func definition was desired, but it probably wasn't the intention in more recent .NET iterations which include their own similar definition.

https://github.com/stuarta0/dbqf/blob/ca2795ee020c40f84e7ba4fcb50b38f97d398c3a/lib/dbqf.core/IListExtensions.cs#L3

I propose this line be changed to include the delegate within the dbqf namespace.