Basic ASCII encoding and decoding
=================================

  Rev 0.12: Changed bytelength to length (thx Steve R)
  Rev 0.11: Slightly simplified calling sequence, based on CriTcl 0.30
  Rev 0.10: Initial release


Implementation of base64 encoding and decoding.  Low-level commands are:

    set text [ascenc::b2a_64 bytes]
        convert string to base64 (input size must be multiple of 3)

    set bytes [ascenc::a2b_64 text]
        convert base64 to string (input size must be multiple of 4)

Built on top, the following commands deal with "full" base64 conversion:

    set text [ascenc::b64encode bytes]
        convert binary string to base64, in lines of 64 chars

    set bytes [ascenc::b64decode text]
        convert base64 to binary string, ignoring newlines and padding