fixed misspelling of exerpt to excerpt for in the Octopress filters

.themes/classic/source/_includes/article.html

@@ -11,7 +11,7 @@
   </header>
 {% endunless %}
 {% if index %}
-  <div class="entry-content">{{ content | exerpt }}</div>
+  <div class="entry-content">{{ content | excerpt }}</div>
   <footer>
     <a rel="full-article" href="{{ root_url }}{{ post.url }}">Read on &rarr;</a>
   </footer>

plugins/octopress_filters.rb

@@ -2,7 +2,7 @@
 
 module OctopressFilters
   # Used on the blog index to split posts on the <!--more--> marker
-  def exerpt(input)
+  def excerpt(input)
     if input.index(/<!--\s*more\s*-->/i)
       input.split(/<!--\s*more\s*-->/i)[0]
     else