Old M220 fixes and added support for 70mm wide tapes

[geeksville]

This PR has fixes to work bettter with M220 printers.

• The key fix is the work done by @bleriotx in https://github.com/vivier/phomemo-tools/pull/15. However, I've merged their three commits into one per a request by @vivier.

But I've also added a second commit that splits out the M220 drv/ppd as its own printer type (rather than using the M110 definition). This was necessary to add support for 70mm wide tapes (which I think the M110 doesn't support?).

Here's an example image of such a tape:

[geeksville]

fixes #13