1. Since our code style dictates that these be `final` methods, we shouldn't be concerned about overlap.
2. There is precedent for `init` methods as requirements before using class instances.
Since we need to maintain backwards compatibility for class constructors we should settle on using method injection instead of constructor injection. I've replaced the `Definition` class we're using with one that doesn't support constructor arguments and added a check for auto_arg addition. Note that we don't check for method existence in the extended container. This is because reflection is unnecessarily expensive and we should avoid it if at all possible.
- `get_instance_of` accepts now arguments to be passed to the
class constructor if necessary.
- `get_special_instance_of` method removed, instead, now if a method
named `get_instance_of_<lowercased class name>` exists in the class,
it is used to get the instance of the class.
- A couple more unit tests added.
- camelCase methods changed to snake_case for consistency with WP.
- Added a check in `ExtendedContainer::get` that throws an informative
exception if a non-namespaced class name is passed.
- `container->reset_resolved()` is called during unit testing bootstrap.
- Added some utility methods in `WC_Unit_Test_Case`.
Christopher Allford
Claudio Sanches
Nestor Soriano