- Some messages should not expire with `PROGRESS_MSG_EXPIRE`.
- Simplify conditional for progress bar with sanity checks.
- Rename `messageTick` to `expireStatusMillis` and make it the expire
time.

- Also a small tweak to SanityCheck.h

/SanityCheck.h:107:53: warning: missing terminating ' character
...

- Add `Conditionals.h` with calculated configuration values
- Add `SanityCheck.h` with checks for configuration errors
- Remove equivalent code from all configurations
- Move error checks from some sources to `SanityCheck.h` also
- Fix initialization of count_direction in stepper.cpp