Support source column widget condition

- Add default HTML anchor widget for source columns that
  return and absolute URL.
- Fix CSS pointer behavior on list item panel headers.

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

mayan/apps/navigation/html_widgets.py

@@ -0,0 +1,15 @@
+from __future__ import unicode_literals
+
+from django.template.loader import render_to_string
+
+
+class SourceColumnLinkWidget(object):
+    template_name = 'navigation/source_column_link_widget.html'
+
+    def render(self, name=None, value=None):
+        return render_to_string(
+            template_name=self.template_name, context={
+                'column': self.column, 'value': value
+            }
+        )
+