Added Last_Accessed_Time to AccountObjectType. Resolves #122
Added AuthenticationType structure to the Account Object schema. Added supporting controlled vocabularies to the CybOX Default Vocabularies. Removed the Password field from the User Account Object since it now exists in the Authentication structure that is inherited from the AccountObjectType.
Added enumeration values and annotations
Moved CVs from the default vocabularies schema to Account Object schema. Created extension type for Structured_Authentication_Mechanism field and removed the xs:anyType type declaration. Added No Password enumeration value to AuthenticationTypeVocab.
Moved StructuredAuthenticationMechanismType higher up in document
Renamed Password field to Authentication_Token. Added a Token_PIN field to AuthenticationType
Changed Authentication_Token field to Password
Renamed Password field to Authentication_Data, set multiplicity on Authentication field to unbounded, and updated AuthenticationTokenProtectionMechanismTypeEnum