Refactor readers for better di (#457)

* Refactor readers to get a proper DI

Similar to what was done with writers, readers also needed to be updated to match the new way of doing things.
This commits promotes a better DI (factories, injection through constructors).

* Escapers should not be singletons

Instead, they should be proper object that can be injected where needed.

src/Spout/Reader/Common/Creator/EntityFactoryInterface.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace Box\Spout\Reader\Common\Creator;
+
+/**
+ * Interface EntityFactoryInterface
+ *
+ * @package Box\Spout\Reader\Common\Creator
+ */
+interface EntityFactoryInterface
+{
+}

src/Spout/Reader/Common/Entity/Options.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Box\Spout\Reader\Common\Entity;
+
+/**
+ * Class Options
+ * Readers' options holder
+ *
+ * @package Box\Spout\Reader\Common\Entity
+ */
+abstract class Options
+{
+    // Common options
+    const SHOULD_FORMAT_DATES = 'shouldFormatDates';
+    const SHOULD_PRESERVE_EMPTY_ROWS = 'shouldPreserveEmptyRows';
+
+    // CSV specific options
+    const FIELD_DELIMITER = 'fieldDelimiter';
+    const FIELD_ENCLOSURE = 'fieldEnclosure';
+    const ENCODING = 'encoding';
+
+    // XLSX specific options
+    const TEMP_FOLDER = 'tempFolder';
+}