REDCORE-278_added mvc override plugin trigger and fixed some code

I would change this name, because the Observer pattern as is implemented in joomla triggers an event, this name looks more like an implicit call (see  https://docs.joomla.org/Supporting_plugins_in_your_component#Joomla.21_Observer_Implementation)

This name is linking MVCoverride plugin with redCORE while the Observed element don't care about who is Observing it, no matter if is redCORE or other Plugin or whoever.

I would instead call it something like: onInclundingPaths, afterIncludingOverridePaths, beforeIncludingOverridePaths... some name that looks more similar to the usual plugin calls in Joomla: https://docs.joomla.org/Plugin/Events