Added authors file.

AUTHORS.rst

@@ -0,0 +1,12 @@
+#######
+AUTHORS
+#######
+
+- Jon Grace-Cox           <jongracecox@gmail.com>
+- run  ``git log --format='%aN' | sort -u`` to see all contributors, or::
+
+      git log --format='%aN <%aE>' |
+        awk '{arr[$0]++} END{for (i in arr){print arr[i], i;}}' |
+        sort -rn | cut -d\  -f2-
+
+  to sort them by the numbers of commits.