Update to use a development version of UCF.
Use the ZipContainer::ZipError in examples and tests.

We hid the rubyzip errors for a reason.
Fixup the example scripts' licence comments.
Use "self" for the File class methods and fix docs.

"self" is more robust to refactoring.
Read the id from the manifest.
Set .ro and .ro/manifest.json to be required entries.
Properly detect missing manifest during creation.
Simple validation of the manifest file.

Just checks for valid JSON at the moment.
Read createdOn and authoredOn info from the manifest.
Add a class to represent an Agent in an RO.
Read createdBy and authoredBy from the manifest.

Return the Agent and list of Agents, respectively.