Grab form spree email from the site config. Closes #78.

contact.html

@@ -5,7 +5,7 @@
 ---
 
 <div class="py2">
-  <form action="https://forms.brace.io/[email protected]" method="POST" class="form-stacked form-light">
+  <form action="https://forms.brace.io/{{ site.email }}" method="POST" class="form-stacked form-light">
     <input type="text" name="email" class="input mobile-block" placeholder="Email Address">
     <textarea type="text" name="content" class="input mobile-block" rows="5" placeholder="What would you like to say?"></textarea>
     <input type="submit" class="button button-blue button-big mobile-block" value="Say Hello">