remove negative margin from .brand in docs, update navbar to support buttons up thurr

lib/patterns.less

@@ -52,6 +52,10 @@
       background-color: transparent;
     }
   }
+  // Buttons in navbar
+  .btn {
+    margin-top: 5px; // make buttons vertically centered in navbar
+  }
 }
 
 // Navbar search