Add Better Exception Messaging

* Verbose Messaging when Vault Tree Exceptions are thrown
* Log the Message to STDOUT
* Pattern for implementing future custom exceptions
Message for VaultDoesNotExistException
Messaging for Unsupported Keyword Exception
Messaging for MissingExternalData Exception
Messaging for MissingPartnerEncryptionKey Exception
Notes for 0.3.7
0.3.7

* clear_exception_messaging:
  Notes for 0.3.7
  Messaging for MissingPartnerEncryptionKey Exception
  Messaging for MissingExternalData Exception
  Messaging for Unsupported Keyword Exception
  Message for VaultDoesNotExistException
  Add Better Exception Messaging