Final release - optimal memory/flash use everywhere.

I've done everything I wanted to do, to optimize the code and move all things I could into flash (program) space. The result is a Forth that can use 1.4K of the Arduino UNO's 2K SRAM. Not bad, especially if you consider that half of the remaining memory is basically reserved for run-time (CPU) stack - and this number can be tweaked.

Lots of FORTH code can fit now...
I proceeded with the "hello world" of the HW universe :-) https://www.youtube.com/watch?v=xePollbCzow

First fully operational release.

• Code cleaned up and commented.
• Passes all tests (AddressSanitizer, Valgrind, and also, in both simavr and real Arduino UNO board).
• All strings moved to Flash (via dprintf, __FlashStringHelper, etc)
• No obvious places where memory/stack are wasted - at least I can't see any...
• Blog post written ( https://www.thanassis.space/miniforth.html )