It looks like I'm finally almost done with this! The only thing left
is gradually replacing "Starfighter.h" imports with imports of what
actually is needed.
This is the last of the data files I wanted to remove.
This commit also includes some dialog changes.
I copied some of this code into a comment elsewhere, because I want
to use it as a reference when creating a new save format.
The only magic numbers left now are related to positioning, image
sizing, and the remaining "data" files (the "planets" and "brief" ones).
At least, I'm pretty sure that's the case.