methods featuring csv delimiter option
* imc_raw.hpp: add print_channel()
* python/{example.py,usage.py}: adjust to existing sample file names,
add print_channel() example
* src/main.cpp: add --delimiter option, additional CLI option checks
methods featuring csv delimiter option
* imc_raw.hpp: add print_channel()
* python/{example.py,usage.py}: adjust to existing sample file names,
add print_channel() example
* src/main.cpp: add --delimiter option, additional CLI option checks