Introduce an options manager for all writers (#423)

This will improve the management of options and simplify some methods' signatures.
This commit will also help moving the code to a better state regarding Dependency Injection.

src/Spout/Writer/Common/Manager/OptionsManagerInterface.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Box\Spout\Writer\Common\Manager;
+
+/**
+ * Interface OptionsManagerInterface
+ * Writer' options interface
+ *
+ * @package Box\Spout\Writer\Common\Manager
+ */
+interface OptionsManagerInterface
+{
+    /**
+     * @param string $optionName
+     * @param mixed $optionValue
+     * @return void
+     */
+    public function setOption($optionName, $optionValue);
+
+    /**
+     * @param string $optionName
+     * @return mixed|null The set option or NULL if no option with given name found
+     */
+    public function getOption($optionName);
+}