Add crates version badge

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README.md

@@ -1,3 +1,4 @@
+[![](http://meritbadge.herokuapp.com/open)](https://crates.io/crates/open)
 [![Build Status](https://travis-ci.org/Byron/open-rs.svg?branch=master)](https://travis-ci.org/Byron/open-rs)
 
 Use this library to open a path or URL using the program configured on the system. It is equivalent to running one of the following:
@@ -33,4 +34,4 @@ Follow this link for the [massive API docs](http://byron.github.io/open-rs).
 
 # Credits
 
-The implementation is based on the respective functionality of [cargo](https://github.com/rust-lang/cargo), but was improved to allow some error handling.
+The implementation is based on the respective functionality of [cargo](https://github.com/rust-lang/cargo), but was improved to allow some error handling.