Release notes:

1. Add a new printer order - sandwich mode: This new order is similar to the outer-wall-first mode in achieving the best dimensional accuracy. This new approach however avoids printing outer walls right after a long travel, which may cause artifacts on the surface in many cases.

2. Support RRF firmware(experimental) 3. Fix a compatibility issue for gcode-preview 4. Merge upstream changes

NOTE 1: For Apple users, please take a look at this article about how to run unsigned applications on your machine.

NOTE 2: Feel free to report issues/bugs/suggestions on GitHub.