Focusing on the diskimg library this time, which deals with a lot of
filesystem structures that have specific widths.
This is still a bit lax in places, e.g. using "long" for lengths.
Should either specify a bit width or use di_off_t.
Also, added "override" keyword where appropriate.
Also, bumped library version to 5.0.0.
Visual Studio figured out variadic macros around 2005, so we can
finally replace the explicit-arg-count debug log macros.
Also, fixed some include guards.
Also, bumped version to 4.0.0d1.
This updates all source files to use spaces instead of tabs for
indentation. It also normalizes the end-of-line markers to be
Windows-style CRLF, and ensures that all files end with EOL.
No substantive changes were made; "diff -w" is empty.