======Lua Hashing Functions======
Added in VPOP3 8.7

Four functions have been added to perform hash algorithms on a text string

  * VPOP3.SHA1(string)
  * VPOP3.SHA256(string)
  * VPOP3.SHA512(string)
  * VPOP3.MD5(string)

All functions take a string parameter, and return a table of numbers containing the hash value (one byte per table entry). The length of the returned table are:
  * SHA1 - 20 bytes
  * SHA256 - 32 bytes
  * SHA512 - 64 bytes
  * MD5 - 16 bytes

If there is an error, the returned table is empty