[IMP] all: new design to match the one on odoo.com

* upgrade to bootstrap 3.3.6

* new Header, port website LESS
  - Add the new header
  - Modify sub-header in order to handle “back” button and version
    switcher
  - Port website’s Less:
    * Use same variables’ names
    * Review fonts and colours in order to fit the new style

* add new footer

* Review and optimise JS code in order properly handle the new header,
  footer and card.top animations

* replace  banner images

_extensions/odoo/static/bootstrap-3.3.6/less/wells.less

@@ -0,0 +1,29 @@
+//
+// Wells
+// --------------------------------------------------
+
+
+// Base class
+.well {
+  min-height: 20px;
+  padding: 19px;
+  margin-bottom: 20px;
+  background-color: @well-bg;
+  border: 1px solid @well-border;
+  border-radius: @border-radius-base;
+  .box-shadow(inset 0 1px 1px rgba(0,0,0,.05));
+  blockquote {
+    border-color: #ddd;
+    border-color: rgba(0,0,0,.15);
+  }
+}
+
+// Sizes
+.well-lg {
+  padding: 24px;
+  border-radius: @border-radius-large;
+}
+.well-sm {
+  padding: 9px;
+  border-radius: @border-radius-small;
+}