Introducing retained flag in modules so they are retained even when the component is unmounted

Introduced a retained flag in IModule that is respected by the RefCounter to keep the module for infinity.

#76: We were not applying ALL of the context values that were provided from ReactReduxContext, so do that here.
When using the createStore prop, we were not providing a modified context to the first connected component. Now, if we call createStore and render a Provider, we will render another instance of DynamicModuleLoader, which will actually add the modules.
While writing this PR, I also decided to simplify the component by removing support for react-redux@5