Upgraded Courier assemblies.
`PersistenceManager.Default` was obsoleted, replaced calls with `ExecutionContext.DatabasePersistence`
Fixed issue with Courier serialization.

When Courier was deserializing, it was treating any nested Archetype as a `JObject`.
The newer serializer routines in Archetype core resolve the previous issue.
Fixed the type-name for the error log messages
Set the project's assembly references to not "Copy Local".

As these pollute the /bin output folder during build.
Bug fix with the Courier resolver
Courier: Turns out that creating a new instance of `PropertyItemProvider` was a hack.

Replaced with getting the item-provider from the existing collection.
Expose serializer for those wanting to create Archetypes from code
Expose FS (fieldsets) and Property (alias/value) for helping with creating Archetype from code
Flip-flop scope and fieldset
Introduced override default propety converter
Fixed type-o
Fixed type-o
Tidy up the PR
Bump version number to v1.6
Update lang files
beta = gtfo
Tweak dropdown position for new fields

See related issue