Minor fix for bad reads on truncated files.
Removed the long-obsolete gif2raw from utils.

Its blithe assumption that the EGA16 palette is correct is now about
20 hyears obsolete. Format conversion is better done with convert(1)
from the ImageMagick suite, anyway.
Typo fix.
Clarification.
Add a reminder.
API change to uncxonditionally free the GifFile structure on close.

Requires a library major version bump and begins the 5.1.x series.
Duplicate code eliminated (SF bug #57).
A bit of code hardening.  All regression tests pass.

This was SF patch #15.
Use a fallback on Windows where mkstemp is not available.

This is SF patch #17.
Document improvements.
Clean up the news summary.
Explicitly initialize the (unused) sort flag.

Almost certainly solves SF bug #52: Failure in testing gifecho.
Ignore some test suite junk made by autotools.
Preparing for 5.1.0 release.
Pacify Coverity scanning.

Sigh, this should hhave been done before release, but these glitches
look harmless. None are in the library.

All regression tests pass,
Update the release procedure.