Fix for Issue 845 - InMemory EnsureCreated() should return true for the
first call to create a database and false thereafter.
Error with the Error Page, "How Meta" - Enable error page for non-collection queries
Exceptions from queries that return a single entity or a scalar value were not triggering the error page as they do not go through MoveNext in our wrapping Enumerable. Adding logging to handle these cases (and applicable unit tests).