Added fallback for navigation container names in view helpers

[froschdesign]

• calling the navigation helper with a parameter navigation is confusing
• name do not corresponds to the documentation
• old name default can be used

Related to an issue of zend-navigation: zendframework/zend-navigation#43

[weierophinney]

Thanks, @froschdesign; pushed to develop for release with 2.9.0

[froschdesign]

@weierophinney Always a pleasure!