Schema mapping should inspect fields that have a matching class property

[rstoyanchev]

Currently schema mapping does not inspect fields that have a matching class property, and generally there is nothing further to do if the field is a scalar or enum, which is the most likely case. However, if the field is a type that contains other fields, then we have to go further. It is an unlikely scenario that implies eager fetching, but from the perspective of schema inspection we need to go as far as we can and depending on what we find.