Add kernel.reset tag on DataCollector to be able to clear memory (#391)

fixes #390

Author: lyrixx

src/Resources/config/data-collector.xml

@@ -15,6 +15,7 @@
 
         <service id="httplug.collector.collector" class="Http\HttplugBundle\Collector\Collector" public="false">
             <tag name="data_collector" template="@Httplug/webprofiler.html.twig" priority="200" id="httplug"/>
+            <tag name="kernel.reset" method="reset"/>
         </service>
 
         <service id="httplug.plugin.stack" class="Http\HttplugBundle\Collector\StackPlugin" public="false" abstract="true">