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/layouts.less

@@ -0,0 +1,17 @@
+//
+// Layouts
+// Fixed-width and fluid (with sidebar) layouts
+// --------------------------------------------
+
+
+// Container (centered, fixed-width layouts)
+.container {
+  .container-fixed();
+}
+
+// Fluid layouts (left aligned, with sidebar, min- & max-width content)
+.container-fluid {
+  padding-left: @gridGutterWidth;
+  padding-right: @gridGutterWidth;
+  .clearfix();
+}