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.

2000/natori/README.md

@@ -0,0 +1,31 @@
+Best Small Program:
+
+    NATORI Shin
+    Univ. of Tokyo
+    Rigakubu 7-goukan 311
+    Hongou 7-3-1, Bunkyou-ku, Tokyo
+    Japan
+
+
+Judges' Comments:
+
+    To build:
+
+	make natori
+
+    To run:
+
+	./natori
+
+    Here is a nice compact program that changes with the phase of the moon.
+    Can you figure out how it does it?
+
+
+Selected Author's Comments:
+
+    This program outputs a rough image of the moon in its current phase.
+    The main obfuscation of this entry is its complicated double recursion
+    (without any loop or conditional statement).
+
+    People living in the southern hemisphere may want to change acos(l/2)
+    into acos(-l/2).