Fixed a possible divide by zero error
Cleaned up some of the id blinding methods (ie. removing handling for impossible error states)
Added unit tests for the new Sodium methods (used for id blinding)
Added unit tests for some of the shared code
Added unit tests for the MessageSender+Encryption extension functions
Added unit tests for the MessageReceiver+Decryption extension functions
Updated the unit test key constants to be consistent with the SOGS auth-example keys for consistency
Added a Nimble predicate for checking a function on a mock was called
Added the various remove methods to the Storage protocol
Updated the Ed25519Type to be an instance-based protocol (needed for mocking)