Initialise CRC Value

#Firmware/v210

v = crc.crc8_init()
v = crc.crc16_init()
v = crc.crc32_init()
v = crc.crcxmodem_init()

Create an initial value for a CRC.

See: crc.crc8_update, crc16_update, crc32_update, crcxmode_update
See: crc.crc8_finish, crc16_finish, crc32_finish, crcxmodem_finish