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/Writer/Common/Entity/Options.php

@@ -4,7 +4,7 @@ namespace Box\Spout\Writer\Common\Entity;
 
 /**
  * Class Options
- * Writer' options holder
+ * Writers' options holder
  *
  * @package Box\Spout\Writer\Common\Entity
  */