Refactored View to use AbstractPluginManager
Refactored View to use AbstractPluginManager

- Helper management
  - Removed HelperLoader and HelperBroker
  - Created HelperPluginManager
  - Refactored PhpRenderer to use HelperPluginManager
- Helpers
  - Removed Navigation\HelperLoader, and replaced with Navigatin\PluginManager
  - Refactored Navigation to use a PluginManager instead of HelperLoader +
    internal registry
  - Fixed HeadLink and HeadMeta helpers; don't look for Pluggable interface, but
    instead duck type on plugin() method
- Forms
  - changed Form HelperLoader to a SM configuration object
  - duck type on plugin() instead of type check on Pluggable
- Refactored Mvc\View\ViewManager to remove references to HelperLoader and
  rename HelperBroker to HelperManager; kept original alias for ViewHelperBroker
  for migration. Moved all plugin mapping to helper manager configuration.
- Ensured all tests related to views, MVC, and forms pass

svycka/zend-mvc,ezimuel/zend-mvc,ezimuel/zend-mvc,MadCat34/zend-mvc,turrsis/zend-mvc,svycka/zend-mvc,MadCat34/zend-mvc,turrsis/zend-mvc