Add a MANIFEST.in

Based on https://github.com/pypa/sampleproject/blob/master/MANIFEST.in

Issue #5 (#5)

MANIFEST.in

@@ -0,0 +1,8 @@
+# Include the README
+include *.md
+
+# Include the license file
+include LICENSE.txt
+
+# Include the data files
+# recursive-include data *