Rewrite the README.

REAME.md

@@ -1,4 +1,19 @@
-# ed25519: Rust implementation
+# ed25519: a Rust implementation
 
-This is a Rust implementation of ed25519 signing and verification.
+Fast and efficient Rust implementation of ed25519 key generation, signing, and
+verification.
 
+# Installation
+
+To install, add the following to the dependencies section of your project's
+`Cargo.toml`:
+
+    ed25519 = "0.1.0"
+
+Then, in your library or executable source, add:
+
+    extern crate ed25519
+
+# TODO
+
+ * Maybe add methods to make exporting keys for backup easier.