* BUG: Some HiDPI fixes.
[GB.FORM]
* NEW: Stock icon default sizes ("small", "medium"...) are now proportional
to Desktop.Scale by steps of 8 pixels. This is for HiDPI support.
* NEW: Wizard BeforeChange event can be cancelled now.
[GB.FORM.MDI]
* NEW: Toolbar tries to update the size of its icons when the font changes.
[GB.GTK]
* NEW: Window now raises a Font event when its font changes.
[GB.GTK3]
* NEW: Window now raises a Font event when its font changes.
[GB.GUI.BASE]
* NEW: TreeView items height padding is now proportional to Desktop.Scale.
[GB.QT4]
* NEW: Window now raises a Font event when its font changes.
[GB.QT5]
* NEW: Window now raises a Font event when its font changes.
git-svn-id: svn://localhost/gambas/trunk@7228 867c0c6c-44f3-4631-809d-bfa615b0a4ec
dfcb60106e