Add [cmd:allowinclude]

Pages must specify whether they want to be included or not.

Otherwise there too many surprises possibe, enforcing access
restrictions will get more complicated

dynamic/dynamiccontentincludepage.cpp

@@ -6,7 +6,11 @@ std::string DynamicContentIncludePage::render()
 	auto rev = revisionDao->getCurrentForPage(this->argument);
 	if(rev)
 	{
-		return rev->content;
+		/* Quite dirty */
+		if(rev->content.find("[cmd:allowinclude]1[") != std::string::npos)
+		{
+			return rev->content;
+		}
 	}
 	return {};
 }