Provide the ability to Serialize and Deserialize

If we provide the ability to serialize and deserialize an object that has been derived from Scaffolding To the engineer Then they will be able to convert objects to &[u8] and vise versa and allowing them to transmit the object To validate this, we will:

[x] Demonstrate that an object can be serialized as json String
[x] Demonstrate that an object can be instantiated (deserialized) from json &[u8]
[x] Ensure that an ActivityItem can be serialized
[x] Ensure that an ActivityItem can be deserialized
[x] Ensure all tests are passing
[x] Confirm documentation is up to date

dsietz / scaffolding-core

Provide the ability to Serialize and Deserialize #19