DB48X: HP48-like RPL implementation for DM42

[c3d]

I'm happy to announce release 0.4.4:

https://github.com/c3d/DB48X-on-DM42/rel...tag/v0.4.4

The main topics in this release are grob objects (with gor, gxor and gand), tagged objects, lastargs / lastx and undo. It is also built and minimally tested both for DM42 (under the name DB48X) and DM32 (under the name DB50X). The DM42 build had to switch to '-Oz' optimization (optimize for size) because I finally hit the flash size constraints on the DM42. So expect the peformance to be a little below 0.4.3.