Rename, convert to Markdown.

README-snapshot.md

diff --git a/README.hg b/README-snapshot.md
similarity index 91%
rename from README.hg
rename to README-snapshot.md
index bd0a124..f38d66c 100644
--- a/README.hg
+++ b/README-snapshot.md
@@ -1,6 +1,6 @@
 To build libzip from the repository using autotools, you need to
 install autoconf, automake, and libtool; then run
-	autoreconf -fi
+> autoreconf -fi
 
 Afterwards you can run configure as usual.