add support to can_unique.py for Cabana CSV format. (#506)
add support to can_unique.py for Cabana CSV format. (#506)

* add support to can_unique.py for Cabana CSV format.

also fix python3 issue where open() was in binary mode, but we want text
mode.

* consolidate duplicated code

* fix typo caught by the linter
commaai/panda,commaai/panda,commaai/panda,commaai/panda