Merged feature/code-pool-selection

Adds functionality for supporting the community code pool, this can be controller by adding a new codepool parameter to the phpspec.yml like so:

````
extensions: [MageTest\PhpSpec\MagentoExtension\Extension]
mage_locator:
  spec_prefix: 'spec'
  src_path: 'public/app/code'
  spec_path: 'spec/public/app/code'
  code_pool: 'community'
````

Code generation and autoloading are working properly. Any instances of the hardcoded local codepool have been replaced with the matching variables and all the generators and locators have been updated.

I'm open to discuss the changes if there are any questions.