packer/depacker for lynx

[sage]

Finally, I decided to release the lynx conversion of the pucrunch packer/depacker.

• lyxass depacker code is included.
  
• working newcc65 code is also existing (but not included, needs some polish)
  
• the depacker code is expecting that the header is skipped partly on ROM file creation (using lynxdir), thus allowing for stream depacking from ROM (like the turbopacker code). This was not working with the imploder code I used for most of my releases. If you use the original header, you have to remove a few comments in the depacker code
  
• The pack rate of pucrunch is better than imploder and much better than turbopacker