- ifd_enumerate: Added utility functions to parse individual, encoded
IFDs and tags.
- ifd_builder: Corrected `NewBuilderTagFromConfig()` to automatically
encode whichever type of value-argument it gets.
- Updated IfdByteEncoder tests to use it instead of hacking-together
their own BT's (makes for more standardized, consistent testing).
- Universally refactored all core IFD knowledge implemented upon a
single IFD name to instead work with IfdIdentity instances, instead,
in order to validate that we only recognize the IFDs only in the
context of the correct parents in the hierarchy.
- Implemented standard testing byte-order (assigned to
TestDefaultByteOrder).
