More detailed description of these commits:
1) FSO: fix bug where shields could be pierced
This patch adds the "$fixed ship-weapon collisions:" flag to the ai_profiles table, fixing a retail bug. When enabled, it keeps shields and thin ship geometry from skipping over incoming weapons. This is most noticeable when flying towards quick weapons in a fighter. The weapon would skip your shields and impact hull directly.
This flag is also enabled for target version 21.4. It is highly recommended for new and under-development mods that have not finished balancing their missions.
2) qtFRED: fix type warning
Behind the scenes technical fix for the qtFRED campaign editor, with no impact on gameplay.
3) qtFRED: Improve CheckedDataListModel
Some improvements to the in-progress qtFRED campaign editor backend.