This is a quick rewrite of Digole's original DigoleSerial library.
Caveat emptor: This library has only been tested by me in my own projects.
While useful, the original was a bit(?) too messy, had some logical flaws (e.g., overriding non-virtual methods from Print), and touchscreen support was somewhat incomplete (probably feature was a late-addition).
In addition, I needed gratuitous excuses for a few things. First, play a bit more deeply with the protocols, SPI, I2C, etc. Second, to play with the idea of compile-time inheritance I had recently seen in a very cool Hackaday project. I ended up "accidentally" buying a logic analyzer and learning more about the linking process, which was fun.
In particular, turns out I knew less about the linking process than I tought I did (talk about false assumptions all these years!); maybe more in a blog post.
U8glib/ucglib uses a neat trick, placing each font constant in a sub-section of it's own. Perhaps I could play similar tricks, but that'd be taking gratuintousness way too far! :) So I just added #defines on top.