Qt 5 has had to be dropped as CMakeLists.txt uses qt_* specific commands
which are implemented in Qt 6 onwards.
cmake --install is only working on Linux at the moment; it installs the
executable and the bundled example tti files into /usr/local/share/doc
The teletext decoder with its document storage has been moved to a
subdirectory with the intention of making it possible to use in other
projects, but some further separation of editing stuff will be needed.
The knowledge of how colour, character etc parameters fit within the
address and data triplets is no longer required. We now present
widgets that explicitly refer to colour, character that are more
user friendly.
