This is needed in order to prepare the transition to GPR2.
Project edition should be done by editing the .gpr files now, with
the help of the Ada Language Server.
Documentation and comments have been updated accordingly and tests
checking the Project Properties GUI have been removed.
For eng/ide/gnatstudio#569
P511-021
Running the Project_Editor_Hook when opening the Project Creation
Wizard has for effect to register default XML-defined tools/switches,
('Builder', 'Ada' etc.) allowing them to be directly editable on the
'Switches' page of the Project Creation Wizard.
Tutorial has been updated accordingly.
Change-Id: Ie27ec791b3b1f8aabef74073e4b78f901db7575e
