Refactored Expression to Expression mapper to use equivalency expression system, from 2 objects and then convert all properties from one type to a constant value from the object.
Issue is expression was chached with the first object used and wouldn't change.
Added ability to convert flattened properties.

Changed mapping using property maps to use property values explicitly instead of pointing to a function that would return the value.
Since using these as the base of Expression to expression for entity framework, it can't figure out uses for invoke and convert.
Merge branch 'AddRemoveExistingCollection' of https://github.com/TylerCarlson1/AutoMapper into AddRemoveExistingCollection