Templatize algorithm::crc32() method

The CRC32 implementation in Drizzle is located in /drizzled/algorithm/crc32.cc. It's declaration is:

uint32_t crc32(const char *key, size_t key_length);

However, most calls of the drizzled::algorithm::crc32() function are made like so:

uint32_t checksum= drizzled::algorithm::crc32(reinterpret_cast<char *>(buffer) - message_byte_length, message_byte_length);

Remove the need for the reinterpret_cast<char *>() call by templatizing the crc32 function.