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/popovers.less

@@ -0,0 +1,49 @@
+// POPOVERS
+// --------
+
+.popover {
+  position: absolute;
+  top: 0;
+  left: 0;
+  z-index: @zindexPopover;
+  display: none;
+  padding: 5px;
+  &.top    { margin-top:  -5px; }
+  &.right  { margin-left:  5px; }
+  &.bottom { margin-top:   5px; }
+  &.left   { margin-left: -5px; }
+  &.top .arrow    { #popoverArrow > .top(); }
+  &.right .arrow  { #popoverArrow > .right(); }
+  &.bottom .arrow { #popoverArrow > .bottom(); }
+  &.left .arrow   { #popoverArrow > .left();  }
+  .arrow {
+    position: absolute;
+    width: 0;
+    height: 0;
+  }
+}
+.popover-inner {
+  padding: 3px;
+  width: 280px;
+  overflow: hidden;
+  background: @black; // has to be full background declaration for IE fallback
+  background: rgba(0,0,0,.8);
+  .border-radius(6px);
+  .box-shadow(0 3px 7px rgba(0,0,0,0.3));
+}
+.popover-title {
+  padding: 9px 15px;
+  line-height: 1;
+  background-color: #f5f5f5;
+  border-bottom:1px solid #eee;
+  .border-radius(3px 3px 0 0);
+}
+.popover-content {
+  padding: 14px;
+  background-color: @white;
+  .border-radius(0 0 3px 3px);
+  .background-clip(padding-box);
+  p, ul, ol {
+    margin-bottom: 0;
+  }
+}