Update plugin.php

Added page_id on {{ navigation:links }}
Useful for use navigator for slideshow or add image on links
Flatter namespace structure and more meaningful classnames
Update Variables module with the new structure
Update Users module
Update Search model
Update Pages module
Update migrations
Update Public controller
Update My_Controller
Updating a few more classes and namespaces
Update File field type
Update blog module
Merge pull request #3089 from luclanet/patch-1

Update plugin.php
Add 5.5 and try fix-missing
Merge branch '2.3/develop' of github.com:pyrocms/pyrocms into 2.3/streams-restructure
Moved methods from drivers to models and removed Data namespace
Update streams parse driver
Update streams cp driver
Update blog, pages, users and variables install
Update page type field management