feat(output): impl PartialEq for Measure

output/src/space.rs

@@ -208,6 +208,13 @@ pub struct Measure<E: Output> {
     pub y: Arc<AtomicUsize>,
 }
 
+impl<E: Output> PartialEq for Measure<E> {
+    fn eq (&self, other: &Self) -> bool {
+        self.x.load(Relaxed) == other.x.load(Relaxed) &&
+            self.y.load(Relaxed) == other.y.load(Relaxed)
+    }
+}
+
 // TODO: 🡘  🡙 ←🡙→ indicator to expand window when too small
 impl<E: Output> Content<E> for Measure<E> {
     fn render (&self, to: &mut E) {