improve docs about buffer option

docs/_includes/options.html

@@ -4,7 +4,7 @@
 <div class="code-block">
   <pre rel="JavaScript"><code class="language-javascript">// Overrideable options
 Shuffle.options = {
-  buffer: 0, // Useful for percentage based heights when they might not always be exactly the same (in pixels).
+  buffer: 0, // Height tolerance. Useful for percentage based heights when they might not always be exactly the same (in pixels).
   columnThreshold: 0.01, // Reading the width of elements isn't precise enough and can cause columns to jump between values.
   columnWidth: 0, // A static number or function that returns a number which tells the plugin how wide the columns are (in pixels).
   delimeter: null, // If your group is not json, and is comma delimeted, you could set delimeter to ','.