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.

tests/Spout/Writer/Common/Manager/OptionsManagerTest.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace Box\Spout\Writer\Common\Manager;
+
+/**
+ * Class OptionsManagerTest
+ *
+ * @package Box\Spout\Writer\Common\Manager
+ */
+class OptionsManagerTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @return void
+     */
+    public function testOptionsManagerShouldReturnDefaultOptionsIfNothingSet()
+    {
+        $optionsManager = new FakeOptionsManager();
+        $this->assertEquals('foo-val', $optionsManager->getOption('foo'));
+        $this->assertEquals(false, $optionsManager->getOption('bar'));
+    }
+
+    /**
+     * @return void
+     */
+    public function testOptionsManagerShouldReturnUpdatedOptionValue()
+    {
+        $optionsManager = new FakeOptionsManager();
+        $optionsManager->setOption('foo', 'new-val');
+        $this->assertEquals('new-val', $optionsManager->getOption('foo'));
+    }
+
+    /**
+     * @return void
+     */
+    public function testOptionsManagerShouldReturnNullIfNoDefaultValueSet()
+    {
+        $optionsManager = new FakeOptionsManager();
+        $this->assertNull($optionsManager->getOption('baz'));
+    }
+
+    /**
+     * @return void
+     */
+    public function testOptionsManagerShouldReturnNullIfNoOptionNotSupported()
+    {
+        $optionsManager = new FakeOptionsManager();
+        $optionsManager->setOption('not-supported', 'something');
+        $this->assertNull($optionsManager->getOption('not-supported'));
+    }
+}
+
+
+// TODO: Convert this to anonymous class when PHP < 7 support is dropped
+class FakeOptionsManager extends OptionsManager
+{
+    protected function getSupportedOptions()
+    {
+        return [
+            'foo',
+            'bar',
+            'baz',
+        ];
+    }
+
+    protected function setDefaultOptions()
+    {
+        $this->setOption('foo', 'foo-val');
+        $this->setOption('bar', false);
+    }
+}