CompositeEntityKeyFactory always reads values as "object"

[ajcvickers]

SimpleEntityKeyFactory objects are created dynamically and are generic on the type of the key property such that the ReadValue method uses the correct type of the key property. This avoids some boxing and also means that, when used with a DataReader, will call the typed reader method. We know that using the typed reader method can be important for some ADO.NET providers that do dynamic conversion based on the expected type.

CompositeEntityKeyFactory objects currently do none of this and just use ReadValue.

[rowanmiller]

SQL Server works at the moment, we'll need to come back to this when we bring SQLite back in.

[ajcvickers]

This code has all changed. Issue is no longer relevant.