#65: CodeRepository/Configuration supports null-repository registration:

```
code_repository:
  type: None
```
#65: CodeRepositoryExtension change is almost ready, waiting for CodeRepositoryExtensionTest
#65: NullCodeRepository implemented / covered by tests.
#65: PHPCS made in CodeRepository/Configuration
Merge remote-tracking branch 'origin/master' into issue_65

Conflicts:
	src/Panza/Library/DependencyInjection/CodeRepository/CodeRepositoryExtension.php
#65: CodeRepositoryExtension: added NullCodeRepository support.
Merge pull request #67 from panza-official/issue_65

Issue 65