More CSV related updates.

app/Import/MapperPreProcess/PreProcessorInterface.php

@@ -0,0 +1,28 @@
+<?php
+/**
+ * PreProcessorInterface.php
+ * Copyright (C) 2016 thegrumpydictator@gmail.com
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE file for details.
+ */
+
+declare(strict_types = 1);
+
+namespace FireflyIII\Import\MapperPreProcess;
+
+/**
+ * Interface PreProcessorInterface
+ *
+ * @package FireflyIII\Import\MapperPreProcess
+ */
+interface PreProcessorInterface
+{
+    /**
+     * @param string $value
+     *
+     * @return array
+     */
+    public function run(string $value): array;
+
+}