Improve example in README.

Import the `Money\Money` namespace and add syntax highlighting for
Github.

README.md

@@ -6,14 +6,19 @@ PHP 5.3+ library to make working with money safer, easier, and fun!
 In short: You probably shouldn't represent monetary values by a float. Wherever 
 you need to represent money, use this Money value object.
 
-    <?php
-	$fiveEur = Money::EUR(500);
-	$tenEur = $fiveEur->add($fiveEur);
-	
-	list($part1, $part2, $part3) = $tenEur->allocate(array(1, 1, 1));
-	assert($part1->equals(Money::EUR(334)));
-	assert($part2->equals(Money::EUR(333)));
-	assert($part3->equals(Money::EUR(333)));
+```php
+<?php
+
+use Money\Money;
+
+$fiveEur = Money::EUR(500);
+$tenEur = $fiveEur->add($fiveEur);
+
+list($part1, $part2, $part3) = $tenEur->allocate(array(1, 1, 1));
+assert($part1->equals(Money::EUR(334)));
+assert($part2->equals(Money::EUR(333)));
+assert($part3->equals(Money::EUR(333)));
+```
 
 The documentation is available at http://money.readthedocs.org