This is a pretty big one! Someone I know suggested that I should
make the textboxes able to stay on the screen for longer, so I've
added an option for that! In the process I also changed Fire and
Altfire to advance to the next box immediately (rather than skipping
outright), so that if you select a slower speed you can still make
the text go to the next one after you're finished reading one.
Problem 1: fullscreen switching was leaving artifacts. Fixed by
drawing all black when switching fullscreen (and switching fullscreen
is now handled by its own function).
Problem 2: the mission briefing screen would distort if you changed
fullscreen during it. Fixed by redrawing the screen (it was previously
only drawn once).
This was done with "replace all" actions, but I have checked and
the only collatoral damage has been to capitalize some instances
of "objective" in comments.
SDL_GetTicks() returns Uint32, but I was using the long int type,
which could mean signed or unsigned, not to mention any size. Changed
missionCompleteTimer and timeTaken to Uint32 for consistency.