#967 PLCgen: don't crash on reading invalid I/O table file.
- Best to review per commit.
- End-user visible changes:
- PLCgen no longer crashes on reading an invalid I/O table file, but instead gives a proper error message.
- Improved PLCgen error messages when reading invalid I/O table files.
- Improved DSM clustering tool error messages when reading an invalid input CSV file.
Closes #967 (closed)