Merge VarienObjectProxy into VarienObjectSubject
As a MageSpec user I would be able to use the following commands:

  - describe:model
  - describe:resource_model
  - describe:block
  - describe:helper
  - describe:controller
Merge branch 'refactoring/varien-proxy' into feature/refactor

Conflicts:
	spec/MageTest/PhpSpec/MagentoExtension/ExtensionSpec.php
	src/MageTest/PhpSpec/MagentoExtension/Extension.php
	src/MageTest/PhpSpec/MagentoExtension/Runner/Maintainer/VarienSubjectMaintainer.php
	src/MageTest/PhpSpec/MagentoExtension/Wrapper/VarienObjectProxy.php
MageSpec users are provided with an up to date documentation.
MageSpec's composer.json should be a valid composer configuration file
README copy&paste errors to be fixed
Merge pull request #30 from MageTest/feature/refactor

Feature/refactor