git mv *.hint -> README.md

There is one exception:

    $ find . -name '*.hint' -execdir git mv '{}' README.md \;
    git statufatal: destination exists, source=1992/albert/albert.hint, destination=1992/albert/README.md

Looking at the two files they differ quite a bit so I've not changed it.
I'll bring this up on GitHub.

1990/dg/README.md

@@ -0,0 +1,57 @@
+Best Abuse of the C Preprocessor:
+
+	David Goodenough
+	anonymous organization
+	541 Commonwealth Ave,
+	Newton, MA 02159
+	USA
+
+Judges' comments:
+
+    Compile and run.  Try:
+
+	echo "to C or not to C" | dg
+
+    Some C preprocessors get confused about single quotes in certain cases.
+    In particular, the following source line:
+
+   Cb12(ase(bco(acp(bi(acp(bcp(acp(bpl(aqu(bqu(A))))))))))))))))))))))))))))))
+
+    may need to be changed to:
+
+   Cb12(ase(bco(acp(bi(acp(bcp(acp(bpl('A'))))))))))))))))))))))))))))
+
+    if your C preprocessor botches single quotes in cpp expansions.
+
+    Systems that have index() and don't strchr() (e.g., BSD) should
+    compile with without -Dindex=strchr.
+
+Selected notes from the author:
+
+    If my preprocessor could hack it, I could write this as one single
+    line rather than 4, but when I do that I get a complaint "defines
+    nested too deeply".
+
+    Spoiler: (rot13 to read)
+
+    Guvf vf nabgure ebg13 wbo (oryvrir vg be abg) - gur #qrsvarf ner n
+    abiry jnl bs nqqvat gbxraf: '#qrsvar o12(k) 12 k' zrnaf gung ng
+    fbzr cbvag va gur fbhepr n 12 vf sbyybjrq ol gur pbzcerffrq arfgrq
+    qrsvarf. Gur o12 trgf gur cerivbhf pbzcerffvba nf na nethzrag, naq
+    cercraqf gur 12, guhf znxvat nabgure fgrc va gur erperngvba bs gur
+    fbhepr. Gur nkk() qrsvarf qb gur fnzr, ohg nqq gbxraf nsgre.
+
+    Nf sbe gur ebg13 nytbevguz, vg eryvrf ba vaqrk() gb svaq vs gur
+    punenpgre vf va gur frg N-Mn-m. y[] vf na neenl gung trgf svyyrq
+    jvgu:
+
+    "abcdefghijklmmmmnopqrstuvwxyzzzzABCDEFGHIJKLMMMMNOPQRSTUVWXYZZZZ"
+
+    Vs vaqrk() fnlf gur pune vf va gur nycunorg, gura kbe gur bssfrg
+    jvgu 16 gb genafyngr, naq bhgchg, bgurejvfr cnff vg hapunatrq.
+
+Copyright (c) 1990, Landon Curt Noll & Larry Bassel.
+All Rights Reserved.  Permission for personal, educational or non-profit use is
+granted provided this this copyright and notice are included in its entirety
+and remains unaltered.  All other uses must receive prior permission in writing
+from both Landon Curt Noll and Larry Bassel.