crc32/16位的校验程序，通俗易懂，实现功能比较完善-crc 32 crc 16

crc校验 包括原理文件和说明 另附有一个crc16的c程序函数和crc32的vc项目文件-CRC checksum, including the principle of documents and a note attached CRC16 function of c procedures and CRC32 of vc project documents

CRC32/16 Routine. Highly optimized for word aligned data. Enable using FAST_CRC macro in the file crc.c