sha204 library extended with CRC calculator

Locking operations are recommended to include CRC
and since sha204 library internally carries the proper
algorithm for this, it has now been refactored to support
both static and incremental calculations needed for both
command marchalling and locking.

libraries/sha204/sha204_library.h

@@ -314,6 +314,7 @@ public:
 			uint8_t tx_size, uint8_t *tx_buffer, uint8_t rx_size, uint8_t *rx_buffer);
 
 	uint8_t getSerialNumber(uint8_t *response);
+	uint16_t calculateAndUpdateCrc(uint8_t length, uint8_t *data, uint16_t current_crc);
 	
 };