Do not show budget graphs if no data

sstreasury/jinja2/sstreasury/budget_view.html

@@ -311,11 +311,15 @@
 	</div>
 	
 	<div class="four wide column">
+		{% if revision.expense %}
 			<p class="ui header">Expenses</p>
 			<canvas id="chartExpenses"></canvas>
+		{% endif %}
 		
+		{% if revision.expense or revision.revenue %}
 			<p class="ui header">Revenue and expenses</p>
 			<canvas id="chartRevExp"></canvas>
+		{% endif %}
 	</div>
 {% endblock %}