Changed the UI::Scrollbar class so it doesn't require subclassing and added functionality for horizontal scrollbars. Fixed the textbox and inventory box scrollbars so their lowest point is consistent with the original engine's.
Removed the BlitType enum and getBlitType() method from RenderObject, and replaced them with setTransparent(). This was done to reduce redundant code, since ManagedSurface can already pick between a transparent and regular blit depending on whether the provided source surface has a transparent color set. Also added the correct transparent color for The Vampire Diaries, and the transparent color for nancy1 now gets calculated on the fly.
Changed surfaces in the textbox and inventory box so they are now initialized with the screen pixel format instead of the one used inside images. With this change The Vampire Diaries no longer fails a particular assert in the ManagedSurface blitting code, and can now boot successfully.
Added generic methods for getting the pixel format and transparent color. Also added a method for loading an image directly into a ManagedSurface, which also loads the palette and lets The Vampire Diaries logo display properly.
Made all states (Scene, Credits, Help, etc.) singletons, as well as subclasses of a common State parent with a proper state switching API. Moved the OnPause virtual function from RenderObject to ActionRecord and hooked it into the state switching code. Also got rid of the NancyEngine pointer that got passed around between most classes, and replaced it with several convenience macros. As a result of these changes action records that render to the viewport no longer disappear after opening the menu, and state changes feel snappier.
Fixed a lot of code formatting issues, including switch case statements being indented, some curly braces not being left hanging, if and for statements not being surrounded by newlines, some double spaces, and more.
The textbox's token parser no longer makes a distinction between captions and responses, and also supports telephone-specific tokens. The code still makes a couple of assumptions about the input text, but those can be fixed in the future if needed.
Rewrote most of the engine using a much more object-oriented approach and using more of ScummVM's common classes. This design deviates quite a lot from the original engine's, but should be more maintainable and extensible in the future.