Kerfly 0.16.0

A version for everyday use: a user guide and website, easier problem reports,
and the K40 Whisperer way of moving the design with the head.

New

• User guide in English and Polish, on the new project website:
  https://cyryllo.github.io/Kerfly/ (Polish).
  In Kerfly, Help → User guide (F1) opens it in the program's language.
• Report a problem on GitHub (Help menu, Bug report button). Kerfly saves a diagnostic
  report and opens the report form with your version, system and board filled in; drag the
  report file into the form. There are forms for laser problems, other bugs, ideas and
  translation fixes, and you can write in English or Polish.
• Design follows the head (the button with a chain link under the unlock button,
  Ctrl+Alt+H). When it is on, the arrows, Go to X/Y and Home move the design together with
  the laser head, as in K40 Whisperer. The corner buttons still only move the head.
  (Not yet tested on a laser.)
• Logo and program icon, in the window and on the taskbar (on Windows, Kerfly now has its
  own taskbar entry instead of Python's).
• README in Polish.

Changed

• Larger jog pad buttons, as tall as the machine buttons beside them.

Install / update

See the installation guide
(Polish). Download the source
code below, unpack it and run start_kerfly.bat (Windows) or ./start_kerfly.sh (Linux).

Full list of changes: CHANGELOG.md