Improvements according to pull request review

Improved valueDelimiter description.
Fixed array example
Added explode string example.

Author: renanliberato

doc/book/validators/explode.md

@@ -6,7 +6,7 @@
 
 The following options are supported for `Zend\Validator\Explode`:
 
-- `valueDelimiter`: Defines the delimiter used to explode the value to an array. It defaults to `,`. If working with an array, this option isn't used.
+- `valueDelimiter`: Defines the delimiter used to explode the value to an array. It defaults to `,`. If the given value is an array, this option isn't used.
 - `validator`: Sets the validator that will be executed on each exploded item.
 
 ## Basic usage
@@ -22,9 +22,24 @@ $explodeValidator = new Zend\Validator\Explode([
     'validator' => $inArrayValidator
 ]);
 
-$value  = [1, 4, 6, 8];
-$return = $valid->isValid($value);
-// returns false
+$explodeValidator->isValid([1, 4, 6]);    // returns true
+$explodeValidator->isValid([1, 4, 6, 8]); // returns false
 ```
 
-The above example returns `true` if all $value items are between 1 and 6.
+## Exploding strings
+
+To validate if every e-mail in an string is into a certain name list:
+
+```php
+$inEmailListValidator = new Zend\Validator\InArray([
+    'haystack' => ['[email protected]', '[email protected]', '[email protected]']
+]);
+
+$explodeValidator = new Zend\Validator\Explode([
+    'validator' => $inEmailListValidator,
+    'valueDelimiter' => ','
+]);
+
+$explodeValidator->isValid('[email protected],[email protected]'); // returns true
+$explodeValidator->isValid('[email protected],[email protected]');  // returns false
+```