Support decoding of tokenized BASIC programs

- Add BASIC de-tokenizer to DragonTools library.
- Add token tables for Dragon BASIC and DragonDos extensions.
- Add -ascii option to DragonDos for decoding BASIC programs read from disk.
- Add script for building and packaging a binary distribution.
- Removing DragonDos documentation.  The README points to the GitHub wiki.
- Update DragonTools version number to 0.3.
- Update DragonDos version number to 0.4.