better header/footer template, add syntax highlighting

templates/branch.html

@@ -1,3 +1,6 @@
+{% extends "base.html" %}
+
+{% block content %}
 branch: {{branch.ref_name}}<br/>
 hash: {{branch.full_hash}} ({{branch.short_hash}})<br/>
 author: {{branch.author.name}}<br/>
@@ -5,3 +8,4 @@ committer: {{branch.committer.name}}<br/>
 date: {{ts_to_date(ts=branch.ts_utc, tz=branch.ts_offset)}}<br/>
 summary: {{branch.summary}}<br/>
 <pre>{{branch.message}}</pre>
+{% endblock content %}