New egg: SRFI-111: Boxes

[noosphere]

I've just ported SRFI-111: Boxes, and would like so submit it for publication.

Its documentation is here: [1]

Its release-info is here: [2]

test-new-egg has given it a clean bill of health.

Although there was a "box" egg for Chicken 4, which was listed on the
"Supported Standards" page as SRFI-111, I chose not to port it to
Chicken 5 because it used different names for its procedures than were
used in SRFI-111, and for compatibility reasons I wanted Chicken 5 to
have completely compliant SRFI-111 support.

So, this SRFI-111 egg is ported directly from the SRFI-111 standard,
without using any code from the "box" egg, except for some tests.

Also, I should note that the "box" egg is actually much more feature
rich than SRFI-111, and is a worthy candidate for porting to Chicken 5
anyway, to give Chicken 5 even more box-related capability.

Finally, on #chicken I asked klovett, the author of the original Chicken
4 "box" egg, about porting SRFI-111 and he said it was ok.

[1] - http://wiki.call-cc.org/eggref/5/srfi-111

[2] - https://github.com/diamond-lizard/srfi-111/raw/main/release-info