Update Session.php

Handle PHP versions < 5.4 when checking if sessions is active.
Merge pull request #44 from robjstanley/patch-1

Update Session.php
Fix bad method call in product fixture
Merge pull request #50 from walterdolce/hotfix/fix-bad-method-call-in-product-fixture

Fix bad method call in product fixture
Fix bad method call in Website helper
Merge pull request #51 from walterdolce/hotfix/fix-bad-method-call-in-website-helper

Fix bad method call in Website helper
Refactor Customer fixture

- Added service container.
- Delegating websites related date responsibility to the Website
  helper class.
Merge pull request #53 from walterdolce/feature/refactor-customer-fixture

Refactor Customer fixture
Add created at to all products created
Fixtures now injected into Factory and maintain state

All fixture classes are now injected to the FictureFactory using the service
configuration. Each fixture now maintains state of the core model it
operates upon meaning reduced need to load resources and evaluate IDs.
Additional excpetion handling and validation is introduced.