changeable equals and hashcode added

src/main/java/ru/touchin/roboswag/core/observables/Changeable.java

@@ -83,4 +83,19 @@ public class Changeable<T> implements Serializable {
         subject = BehaviorSubject.create((T) inputStream.readObject());
     }
 
+    @Override
+    public boolean equals(final Object object) {
+        if (this == object) return true;
+        if (object == null || getClass() != object.getClass()) return false;
+
+        final Changeable<?> that = (Changeable<?>) object;
+        return subject.getValue() != null ? subject.getValue().equals(that.subject.getValue()) : that.subject.getValue() == null;
+
+    }
+
+    @Override
+    public int hashCode() {
+        return subject.getValue() != null ? subject.getValue().hashCode() : 0;
+    }
+
 }