v1.3.7-alpha

This is only a semi-official release that may remain alpha forever.
But since the automatically built .hex file from the dev/build branch expires after a while…

Includes:

• Fix the weird screen glitch issue
• Add an additional blanking mode in addition to the visualizations. The timeout can be configured in the calibration menu, or it can be activated manually (long-press up, or up when screensaver active)
• Built via github workflow with platformio. This is a different toolchain than previous official releases. Hence it should be considered experimental and not robustly tested.