Complete HERA API

As of 1.0, the following function remain unimplemented:

• replaceProperty:
  • implement it
  • unit test it
  • document it
• replaceItem:
  • implement it
  • unit test it
  • document it
• updateItem:
  • implement it
  • unit test it
  • document it
• deleteMetadata:
  • implement it
  • unit test it
  • document it
• replaceEntity:
  • implement it
  • unit test it
  • document it
• replaceAttribute:
  • implement it
  • unit test it
  • document it