[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/mixins/pagination.less

@@ -0,0 +1,24 @@
+// Pagination
+
+.pagination-size(@padding-vertical; @padding-horizontal; @font-size; @line-height; @border-radius) {
+  > li {
+    > a,
+    > span {
+      padding: @padding-vertical @padding-horizontal;
+      font-size: @font-size;
+      line-height: @line-height;
+    }
+    &:first-child {
+      > a,
+      > span {
+        .border-left-radius(@border-radius);
+      }
+    }
+    &:last-child {
+      > a,
+      > span {
+        .border-right-radius(@border-radius);
+      }
+    }
+  }
+}