- Move "Mono" popup menu from the top right corner to `Projects -> Tools` as a submenu.
- Add "Build solution" button to the top right corner. Makes it more visible and quicker to access.
- Fix build list in the bottom panel unselect an item when clicking on empty space. Previously it would hide the issues panel but the item would remain selected, making it impossible to display the issues panel again if there was only one item.
Using `misc/scripts/fix_headers.py` on all Godot files.
Some missing header guards were added, and the header inclusion order
was fixed in the Bullet module.
