WJ200_vfd commit
wj200: compile wj200 driver
wj200: enable wj200 driver if libmodbus3 is present
wj200: expose comp instance to print_modbus_error()

This prevents a guaranteed segfault when this function is called.
wj200: #include ctype.h, needed for toupper()
wj200: rename pin to match naming convention

CamelCase violates the HAL General Naming Convention, so rename the
is-atSpeed pin to is-at-speed.
wj200: make the manpage