Do not fail if no equipment has been defined.

Fixes #112.

lib/www/server/lib/sse/prepare.js

@@ -6,8 +6,10 @@ async function prepare (project, query) {
 	const equipment = await info.get(null, "equipment");
 	for (const sequence of sequences) {
 		const maxTstamp = sequence.ts1_final || sequence.ts1 || +Infinity;
+		if (equipment) {
 			sequence.equipment = equipment.filter(i => new Date(i.tstamp) <= maxTstamp);
 		}
+	}
 	return {events, sequences};
 }