Added/updated tests

src/main/java/de/rwu/easydrop/util/Config.java

@@ -109,4 +109,11 @@ public final class Config {
     public void setProperty(final String key, final String value) {
         properties.setProperty(key, value);
     }
+
+    /**
+     * Resets the config's properties.
+     */
+    public void reset() {
+        properties = null;
+    }
 }