Add 2019/dogon/try.sh, update bugs.md, README.md

Updated Makefile so one can easily change the 'Z' macro by doing:

    make clobber MEMORY=... all

This is not usually useful but there are occasions where it is. As the
README.md points out this value must be a power of two!

The try.sh script runs the program on a number of the mc files, first
showing the input keys as a reminder (it also reminds one to keep in
mind the focus of windows).

The bugs.md is updated to note that it uses gets(3).

Format/typo check README.md file.

I changed the number of years ago that microorganisms appeared on Earth
as the number was off: there are those wondrous hydrothermal vents that
spewed mineral rich waters. Fun fact on the history of the Earth: did
you know that as of 2013 the number of years since the dinosaurs were
wiped out is not 65m years but actually 66m? That means that if you were
born before 2013 and you didn't die right before the revision that
you're in a rare group of people who have had a major historical update
as far as the dinosaurs go. But don't let it get to your head too much!
It also means you're ancient, possibly even a dinosaur, and you're
headed their way. :-) That's the price we must pay for being in that
group.

bugs.md

@@ -3313,6 +3313,15 @@ in the de.sh/de.alt.sh scripts:
 # reason that so many words have them.
 ```
 
+## 2019 dogon
+
+### STATUS: uses gets() - change to fgets() if possible
+### Source code: [2019/dogon/prog.c](2019/dogon/prog.c)
+### Information: [2019/dogon/README.md](2019/dogon/README.md)
+
+The author does not it uses `gets()` and one will get warnings but it would be
+ideal if this was not the case.
+
 
 ## 2019 duble