Resolve #5 - implement a few 'canned' deserialization functions

This solution uses extension methods to map some simple deserialization
scenarios (strings, numeric values and enumerations).
Upgrade CSF.Core to version 3.0.0
Upgrade target framework version to 4.0
Fix failing test (simple namespace removal)
WIP #2 - Remove all entity serialization/deserialization functionality
Resolve #2 - Adds functionality to deserialise as an entity identity

This adds canned deserialization functionality to deserialize a simple property
as an entity identity.

* Also consolidate two sets of integration tests.

* Add new integration test for deserializing using extension methods.
Merge branch 'feature/2-entity-mapping'