Clean up PHPCS Suggestions
Add alias support to DI
Add outline for new documentation
Start updating documentation.
Update documentation
Clarification. Fix spelling mistake.
Update CS on the tests. Move test stubs to own file.
Allows the DI container to set a callable value.
Update documentation for the new feature.
Modify code per feedback.
Cleanup based on phpdoc output and file review
Fix up a heap of code-style issues.
Adding container->exists method and test
Updated as per dongilbert's comments
docblock fix