New features in Claims specification require changes here

[technosophos]

• created is required fix: formalize the field definitions on the Claims spec. cnab-spec#295
• bundleReference is added add bundleReference to the claim specification cnab-spec#299
• Claims must be mounted at /cnab/claim.json add CNAB_CLAIMS_VERSION and mount path for claim.json cnab-spec#300
• CNAB_CLAIMS_VERSION must be set in the invocation image