Executors: add Ringa.inject() wrapper

[joshjung]

Target Code:

import {inject} from 'ringa';

controller.addListener('test', [
  Executor1,
  inject(Executor2, {
    property1: 'some value'
  }),
  Executor2
]);

When Executor2's is executed the following occurs:

CommandAbstract and CommandFunctionWrapper: the injection Object is merged into the standard injections for the execute() method.

CommandEventWrapper: the injection Object becomes the details for the event.

Note: we may want to consider allowing Executor2 to be its own chain, but I think that will make complexity go through the roof right now.