Make page titles and headers consistent. Advances BiscuIT-ng#65.

biscuit/apps/chronos/templates/chronos/edit_substitution.html

 {% extends "core/base.html" %}
 {% load bootstrap4 i18n %}
 
+{% block bootstrap4_extra_head%}
+    <title>{% block bootstrap4_title %}{% blocktrans %}BiscuIT SIS - Add book{% endblocktrans %}{% endblock %}</title>
+{% endblock %}
+
 {% block page_title %}{% blocktrans %}Edit substitution{% endblocktrans %}{% endblock %}
 
 {% block content %}

biscuit/apps/chronos/templates/chronos/lessons_day.html

@@ -2,6 +2,10 @@
 {% load bootstrap4 i18n font_awesome %}
 {% load render_table from django_tables2 %}
 
+{% block bootstrap4_extra_head%}
+    <title>{% block bootstrap4_title %}{% blocktrans %}BiscuIT SIS - Add book{% endblocktrans %}{% endblock %}</title>
+{% endblock %}
+
 {% block page_title %}{% blocktrans %}Lessons{% endblocktrans %}{% endblock %}
 
 {% block content %}

biscuit/apps/chronos/templates/chronos/tt_week.html

@@ -4,10 +4,11 @@
 
 {% block bootstrap4_extra_head %}
  {{ block.super }}
+ <title>{% block bootstrap4_title %}{% blocktrans %}BiscuIT SIS - Timetable{% endblocktrans %}{% endblock %}</title>
  <link rel="stylesheet" href="{% static 'css/chronos/timetable.css' %}" />
 {% endblock %}
 
-{% block page_title %}Timetable{% endblock %}
+{% block page_title %}{% blocktrans %}Timetable{% endblocktrans %}{% endblock %}
 
 {% block content %}
  <form method="get">