Update README.md with raw downloadable install url

I tried to download the jquery.matchHeight.js download link by using "save link as...", and I got a .js file with html content. Realized it links to the repo with the file, so I propose to link to the raw file instead. This will make it directly downloadable.

Author: robeerob

README.md

@@ -53,7 +53,7 @@ See how others are using jquery.matchHeight.js
 ### Install
 
 [jQuery](http://jquery.com/download/) is required, so include it first.
-  Download [jquery.matchHeight.js](https://github.com/liabru/jquery-match-height/blob/master/jquery.matchHeight.js) and include the script in your HTML file:
+  Download [jquery.matchHeight.js](https://raw.githubusercontent.com/liabru/jquery-match-height/master/jquery.matchHeight.js) and include the script in your HTML file:
 
 	<script src="jquery.matchHeight.js" type="text/javascript"></script>