Refactor Product fixture, introduce helpers

- Refactored Product fixture removing unneeded responsibility
  and by introducing the concept of "helpers".
- Added Website helper
- Adjusted ProductSpec accordingly
- Commented CoreConfigSpec causing PhpSpec to return non-zero value
Refactor Product fixture

- Removed unnecessary constant
Refactor Website helper

- Removed unnecessary code
Refactored Website helper, Product & ProductSpec

- Added service container in Product fixture
- Added DocBlock in Website helper according to standard one
Merge pull request #49 from walterdolce/feature/refactor-product-fixture-introduce-helpers

Refactor Product fixture, introduce helpers