View helper / controller plugin managers should not peer with main SM
View helper / controller plugin managers should not peer with main SM

Added getter/setter for the main ServiceManager in the
AbstractPluginManager so that factories can still have access to the
main SM if needed.

akrabat/zend-servicemanager,MadCat34/zend-servicemanager,matwright/zend-servicemanager,weierophinney/zend-servicemanager,prolic/zend-servicemanager