Ensure Navigation helper PluginManager is BC

[weierophinney]

Adds tests similar to those for the HelperPluginManager to ensure that the first argument to the Navigation\PluginManager is optional and/or accepts a Zend\ServiceManager\Config instance, and updates the constructor to work with both v2 and v3.

Fixes zendframework/zend-navigation#19 and zenframework/zend-view#45

[weierophinney]

Most recent changes also address the alias resolution reported in #46.

[weierophinney]

In a private email, @webimpress has indicated that the initializers registered by HelperPluginManager are not receiving a container instance; I'm going to investigate that before merging.

[weierophinney]

Okay, what I've discovered is that Zend\View\Helper\Navigation lazy-loads Zend\View\Helper\Navigation\PluginManager by default. This means that it doesn't have a parent service manager instance, which in turn means that the initializers it registers due to inheriting from Zend\View\HelperPluginManager do not have a parent locator instance, and thus cannot be injected with things like the translator.

Under v2, this worked because of this line:

• zend-view/src/HelperPluginManager.php

  Lines 153 to 155 in f1b6826

  	if (!$locator) {
  	return;
  	}

which essentially made it so that the navigation plugins, even if translator-aware, are never injected with a translator.

I'll re-instate that behavior for now, and later, when preparing zend-navigation for forwards-compatibility, I'll set it up to create a navigation plugin manager that's injected with the parent locator of the helper plugin manager.

[froschdesign]

Looks good!

[gianarb]

Good 👍 2.6.2 works fine for me.. Thanks