- introduced new show command to display configuration settings
- config command is used to just set config values
- modified documentation
- modified some unit tests calling 'task config' to 'task show'
- version now only displays the version number and copyright notice
- config displays the task configuration that version used to show
- configuration variable longversion is not longer needed
- The 'version' command now complains about use of deprecated color names and
duplicate entries.
- Unit tests verify duplicate detection.
- Unit tests verify deprecated color detection.
- Most validation code moved from command.cpp to Config.cpp.
