Update templates & fix carousel bugs

Templates now have date of 2019 BBC Young Reporter day on them;
Carousel bug whereby if a dot was clicked & then the used scrolled away, 
the dot would turn black;
Dots now appear in the correct position on all screen sizes (they were 
too low on mobile).

_includes/article-carousel.html

@@ -4,13 +4,15 @@
         {% if article.url != page.url %}
         {% assign authors = article.authors | split: ", " %}
         {% for author in authors %}
-            {% if article.date | date: "%Y" == page.date | date: "%Y" %}
+            {% assign article_date = article.date | date: "%Y" %}
+            {% assign current_article_date = page.date | date: "%Y" %}
+            {% if article_date == current_article_date %}
             {% assign current_authors = page.authors | split: ", " %}
             {% for current_author in current_authors %}
                 {% if author == current_author %}
                     {% if article_list_displayed == false %}
                     <h2 class="mdc-typography--headline5">
-                        {% if current_authors.first %}
+                        {% if current_authors.size > 1 %}
                         Other Articles By These Authors
                         {% else %}
                         Other Articles By This Author