Method should depend on IObjectInfo
Moved MemberInfoExtensions to Mapping namespace

It's only used by the attribute mapping convention
Closes #351

Move the mapping attributes into an Attributes subnamespace of Mapping
Closes #352

Move DbEncryptedString and associated classes into a new
MicroLite.Extensions.Cryptography assembly
Reduce usage of IHideObjectMethods

Only implement IHideObjectMethods in interfaces which are used as part
of a fluent API or part of the session API