Remove all frameworks except Bootstrap (#251)

- Remove all frameworks except Bootstrap

- Remove roots-options.php and replace with a more simple
  roots-config.php

- Include all Bootstrap Javascript plugins by default in
  js/plugins.js

- Use Bootstrap Responsive and Topbar navigation by default

- Use Bootstrap markup on forms, page titles, image galleries,
  alerts and errors, post and comment navigation

- Remove Roots styles from style.css and introduce app.css for
  site-specific CSS. Remove almost all previous default Roots
  styles.

- Add latest updates from H5BP project

css/less/close.less

@@ -0,0 +1,18 @@
+// CLOSE ICONS
+// -----------
+
+.close {
+  float: right;
+  font-size: 20px;
+  font-weight: bold;
+  line-height: @baseLineHeight;
+  color: @black;
+  text-shadow: 0 1px 0 rgba(255,255,255,1);
+  .opacity(20);
+  &:hover {
+    color: @black;
+    text-decoration: none;
+    .opacity(40);
+    cursor: pointer;
+  }
+}