Terminal/e4thcom dual-mode, lots of editing

[TG9541]

Hi Richard, this pull request has three goals:

1. allow efficient program/edit cycle even without e4thcom
2. split library code, board configuration, and application (work in progress)
3. editing: allow usage in a case-sensitive systems, try to use "Brody style"

1.) will speed up your programming cycle with "dumb terminals" quite a bit It works in the following way:

• flash the STM8 eForth binary (e.g. MINDEV.ihx)
• transfer Depend (which words normally loaded with #require or \res, and makes Forth ignore #require etc
• Depend creates a persistent vocabulary
• transfer Core and run PERSIST (unless you're coding/testing Core, of course)
• transfer the application code, e.g. Ping

2.) I'm trying to find a way for splitting core code from configuration, ans application code from the latter. This is a bit tricky.

3.) Uniform formatting is nitpicking but lower/uppercase is a question of compatibility with the CORE binary.