New firmware for the Swissmicros DM15L

[jebedeo]

Thanks for pointing out those bugs!

They should be fixed now. I found the root cause of the arctan(1) bug and it comes from using an old version of the c library for arm MCUs, newlib. It's not fixed yet but I have a path for it.

The 0 was indeed being ignored during a program, nice catch!

John, STO and RCL need to be terminated with ENTER on purpose. It's a behavior from the hp42, and the reason is that we have 99 registers so more than one digit is needed. Also, if you make a mistake while picking the register, you can just press the <- button.