update wording

Author: nginnever

README.md

@@ -67,8 +67,8 @@ A valid (read: that follows this interface) IPFS core implementation, must expos
 
 `multihash` is a [multihash][] which can be passed as
 
-- Buffer, the raw Buffer of the multihash (or of and encoded version)
-- String, the toString version of the multihash (or of an encoded version)
+- Buffer, the raw Buffer of the multihash 
+- String, the base58 encoded version of the multihash
 
 `callback` must follow `function (err, stream) {}` signature, where `err` is an error if the operation was not successful and `stream` is a readable stream of the file.