This was originally generic and used by YAPF, but now it is used only by script objects.
CCountedPtr provided much more (untested) functionality than used.
ScriptObjectRef already exists for script objects and does the same thing, so use this instead.
Adds GSStoryPage::IsValidStoryPageButtonColour, GSStoryPage::IsValidStoryPageButtonFlags and GSStoryPage::IsValidStoryPageButtonCursor to the API.
Add missing enforced preconditions to validate parameters passed to MakePushButtonReference, MakeTileButtonReference and MakeVehicleButtonReference.
Fixes a crash that happens if an invalid StoryPageElementType is passed to ScriptStoryPage::NewElement.
Adds an enforced precondition that tests the validity of StoryPageElementType.
Adds GSStoryPage::IsValidStoryPageElementType to the API.
Direct 1:1 replacements in the code, and comments now refer to either
GSCompanyMode::IsValid or GSCompanyMode::IsDeity instead of several variations
on "company mode active" or "no company mode active".
Allow more direct player-initiated interaction for Game Scripts, by letting the GS put push-buttons on storybook pages. These buttons can either trigger an immediate event, or require the player to first select a tile on the map, or a vehicle.
Additionally this reworks how the storybook pages are layouted and rendered, to allow for slightly more complex layouts, and maybe speeding drawing up a bit.
