Compression algorithm:
----------------------
Digits '0' (0x30) to '9' (0x39) compress to nibble 0 to 9

Characters from 0x00 to 0x5F compress by adding 0xA0
and writing two nibbles.

Leading byte indicates length (including length byte, ie: datalen+1)
Unused nibble is padded with 'F'

Memory Layout:
--------------
All locations not specified contain 00
At 0000, file contains: 'IF@@OOOO'
Word at 0080 contains 16 bit sum of bytes from 0086 to end of image.
Word at 0082 contains first free data address (xxx - 9E4A) + 08CA
Byte at 0086 contain 0x07
Byte at 0087 contains password length (including length = +1)
Password is stored at 0x0088
Byte at 0093 contains 0x96
Word at 0094 contains 0xFFFF
Words from 00A0-00F9 contain 01 00
Pointer table begins in image at 0x00FA
Compressed data begins in image at 0x08CA (0x00FA + 1000*2)

Predefined TRANZ locations:
---------------------------
Location 002 is preset to 8900 pointer (no memory block)
Location 003 is preset to 8A00 pointer (no memory block)
Location 004 is preloaded with 04 000000
Location 005 is preloaded with 03 0000
Location 018 is preloaded wtih 09 0000000000000000
