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.css

@@ -81,6 +81,7 @@ input[type="text"] {
 label {
     display: inline-block;
     width: 170px;
+    vertical-align: top;
 }
 
 label[for=rememberSpeed] {