Improve IMFS robustness with out-of-order events

Fixes #111.

test-scratch-project

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+# Copies a project from 'test-projects' into a folder that can be messed with
+# without accidentally checking the results into version control.
+
+set -e
+
+if [ ! -d "test-projects/$1" ]
+then
+	echo "Pick a project that exists!"
+	exit 1
+fi
+
+if [ -d "scratch-project/$1" ]
+then
+	rm -rf "scratch-project/$1"
+fi
+
+mkdir -p scratch-project
+cp -r "test-projects/$1" scratch-project
+cargo run -- serve "scratch-project/$1"