Issue #16 Money Value Object for related entities

Entities having "price" attributes were refactored so that a Money value
object can be used for currency arithmetics (add, subtract, multiply by
factor operations).

A price is a Money value object, and is defined by an integer amount and
a Currency. Consequently, any entity that works with Money now has a
Currency, let alone the money amount (that now is an *integer* value)

Entities using Money will *need* to be factored with a consistent
Currency object, and their factory classes were changed accordingly.
Merge pull request #92 from elcodi/money-value-object

Issue #16 Money Value Object for related entities
Fixed incorrect expected value in test
Fixed more incorrect expected values in test
Refactored CartBundle

* Added more useful functional and unit tests
* Refactored managers, and uncoupling them a little bit more
* Uncoupled as much as possble all managers with ObjectManager
* Updated entity relation mapping definitions
    * Added orphanRemovals
    * Added properly all cascade definitions
* Added by default buildSchema in WebTestCase
* Fixed CartCoupon to work properly with these changes
* Added some minor tests in CartCouponBundle
* Passed php-cs-fixer
WIP
WIP
WIP