Render promotions within content block of layout.html

Promotions were omitted from the main layout block (accidentally I
imagine).  I think they used to be there - perhaps a template refactor
stripped them out.

This commit reinstates them so pages that use the default layout
template (like flatpages) can have promotions added to them.

oscar/templates/oscar/flatpages/default.html

 {% extends "layout.html" %}
 
 {% block title %}
-{{ flatpage.title}} | {{ block.super }}
+    {{ flatpage.title}} | {{ block.super }}
 {% endblock %}
 
 {% block headertext %}
-{{ flatpage.title }}
+    {{ flatpage.title }}
 {% endblock %}
 
 {% block content %}
-<article>{{ flatpage.content|linebreaks }}</article>
+    <article>{{ flatpage.content|linebreaks }}</article>
 {% endblock %}

oscar/templates/oscar/layout.html

 {% extends "base.html" %}
 {% load compress %}
+{% load promotion_tags %}
 
 {% block layout %}
     {# Top-horizontal bar with account, notifictions, dashboard links #}
             {% block subnavigation %}{% endblock %}
             <div class="content">
                 {% block subheader %}{% endblock subheader %}
+
+                {# Render promotions #}
+                <div id="promotions">
+                    {% for promotion in promotions_page %}
+                        {% render_promotion promotion %}
+                    {% endfor %}
+                </div>
+
                 {# Div exists for AJAX updates to entire content section #}
                 <div id="content_inner">{% block content %}{% endblock %}</div>
             </div>