Converted hook_menu_link_defaults() to .links.menu.yml file (https://www.drupal.org/node/2228089)
Changed theme() calls to _theme() (https://www.drupal.org/node/2195739)
Fixed error handling in Form\SetupForm.
Created an EventSubscriber to contain the hook_boot() code.
Merge pull request #3 from phenaproxima/8.x-2.x

UI fixes