Roll back ad04d21fda

As was discussed with Landon this was a mistake even if it helped with
consistency. There was even a brilliant pun that was destroyed with that
commit which I think is worth pointing out:

    cp README.md hill
    ./ant hill

in 1991/ant ... even if it's technically 'anthill'.

I hope that I got all links fixed in years.html and winners.html. As
well I tried to make sure I got all handles fixed in all/summary.txt.
Nevertheless these should be checked. For some handles they were never
updated (at least in the html files - though maybe summary.txt too, not
sure) in the first place so there was nothing to do.

Typo fixes like references to *.hint when it should be README.md. There
probably are others that need to be fixed but haven't been located yet.

1990/.gitignore

@@ -1,5 +1,5 @@
 baruch/baruch
-mills/mills
+cmills/cmills
 dds/dds
 dg/dg
 jaw/atob
@@ -10,9 +10,9 @@ scjones/scjones
 stig/o
 stig/o.c
 tbr/tbr
-mariano/fibonacci
-mariano/fibonacci.c
-mariano/sorter
-mariano/sorter.c
-mariano/mariano
+theorem/fibonacci
+theorem/fibonacci.c
+theorem/sorter
+theorem/sorter.c
+theorem/theorem
 westley/westley