fix a format string error introduced in the XS re-work
fix the test skip count for 350-font/030-ttoo.t
adjust the IEEEFP check for older versions of perl

without the byte order pack modifier
skip an alarm using test if the perl signal detection is broken

Like 5.6.2 in my Ubuntu 32-bit VM
Imager 0.96_01 release
Changes typo fixes
[rt #86659] treat a libpng header/lib version mismatch as probe failure
[rt #86658] scan MANIFEST for pod to check, not blib

Not all the files are always installed
[rt #86658] add a missing AUTHOR heading