Fix issue #16 https://github.com/cfortune/PHP-Bounce-Handler/issues/16

[rbairwell]

Fixes the use of /e in preg_replace as per @Orayi suggestion in https://github.com/cfortune/PHP-Bounce-Handler/issues/16 (see commit 165ce06 ).

Lots of other changes including:

• Change code formatting to be based more on PSR1/2 and Symfony styles
• Added PHPDocumentor blocks (not all methods/properties are fully commented, but it is a start!)
• Replaced split() (which is depreciated) with explode and preg_split
• Fixed a number of code smells (undefined variables, missing quote marks around array members, unusued functions)
• Allow for bounce_responses.php and bounce_statuscodes.php to be optional (the constructor and fetch_status_messages now allow the details to be passed in and will only load those files if there is missing information)