+/* CRC16 implementation acording to CCITT standards.
+ *
+ * Note by @antirez: this is actually the XMODEM CRC 16 algorithm, using the
+ * following parameters:
+ *
+ * Name : "XMODEM", also known as "ZMODEM", "CRC-16/ACORN"
+ * Width : 16 bit
+ * Poly : 1021 (That is actually x^16 + x^12 + x^5 + 1)
+ * Initialization : 0000
+ * Reflect Input byte : False
+ * Reflect Output CRC : False
+ * Xor constant to output CRC : 0000
+ * Output for "123456789" : 31C3
+ */