add user defined blacklist

Moving some of the previously blacklisted sites to user controlled
blacklist. Remaining sites in manifest are blocked due to interop
issues.

Closes #121.

options.html

@@ -35,7 +35,7 @@
     </section>
 
     <section>
-			<h3>Others</h3>
+			<h3>Other</h3>
   		<div class="row">
           <label for="rewindTime">Rewind Time (s)</label>
           <input id="rewindTime" type="text" value=""/>
@@ -52,6 +52,10 @@
           <label for="rememberSpeed">Remember Playback Speed</label>
           <input id="rememberSpeed" type="checkbox"/>
       </div>
+      <div class="row">
+          <label for="blacklist">Blacklisted sites on which extension is disabled<br/>(one per line)</label>
+          <textarea id="blacklist" rows="10" cols="50"></textarea>
+      </div>
     </section>
 
     <button id="save">Save</button>