This platform was supported by Sierra for early and pri-AGI games.
CoCo 1 and 2 were not generally forward compatible with CoCo 3,
which was officially supported by Sierra for KQ3 and LSL1 only.
These can be big- or little-endian. The development platform can be
autodetected based on RIFX/XFIR in header.
These games ran in Shockwave Player either as a standalone app or as
web browser plugins on Windows and Mac.
Shockwave game added as D6 detection entry as an example.
Adding @defgroup and @ingroup doxygen tags into all headers
in the common folder that contain doxygen blocks.
This improves the structure, readability, and findability
of information in the resulting output.
This commit targets purely structure and does not deal with
the content of the currently existing doxygen documentation.
