Add Tests

[mghenderson]

As new mappings are being added, and updates made within the code, extend the tests to cover those changes.

• LinkObj
• EmailMessageObject
• CFM13 to STIX TLP combinations (multiple alerts in a file, w/ different restrictions)
• Time entries (e.g. ProducedTime, CreatedTime)
• STIX profiles
• Support for controlled_structure node (//node() || @*")