[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/bootstrap.less

@@ -0,0 +1,56 @@
+/*!
+ * Bootstrap v3.3.6 (http://getbootstrap.com)
+ * Copyright 2011-2015 Twitter, Inc.
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+ */
+
+// Core variables and mixins
+@import "variables.less";
+@import "mixins.less";
+
+// Reset and dependencies
+@import "normalize.less";
+@import "print.less";
+@import "glyphicons.less";
+
+// Core CSS
+@import "scaffolding.less";
+@import "type.less";
+@import "code.less";
+@import "grid.less";
+@import "tables.less";
+@import "forms.less";
+@import "buttons.less";
+
+// Components
+@import "component-animations.less";
+@import "dropdowns.less";
+@import "button-groups.less";
+@import "input-groups.less";
+@import "navs.less";
+@import "navbar.less";
+@import "breadcrumbs.less";
+@import "pagination.less";
+@import "pager.less";
+@import "labels.less";
+@import "badges.less";
+@import "jumbotron.less";
+@import "thumbnails.less";
+@import "alerts.less";
+@import "progress-bars.less";
+@import "media.less";
+@import "list-group.less";
+@import "panels.less";
+@import "responsive-embed.less";
+@import "wells.less";
+@import "close.less";
+
+// Components w/ JavaScript
+@import "modals.less";
+@import "tooltip.less";
+@import "popovers.less";
+@import "carousel.less";
+
+// Utility classes
+@import "utilities.less";
+@import "responsive-utilities.less";