Use Ref::INVALID more
In this case we have to be a bit more careful since we're changing code that used to assign to 0,0 and now INVALID is -1, -1 but i'm confident it's fine
inReplyTo seems to be only used in qt5/src/poppler-annotation.cc and i've updated the code to use the boolean isInReplyTo instead of checking the ref number directly
The change in Dict only affects its two callers, one in Annot and one in Catalog. The one in catalog has been updated, the one in Annot doesn't seem to need updating (and moreover if you check history before using the new Dict function was using -1, -1 as ref not initialized)
The change in Array only affects its one caller, in Function, whose code has been updated
The embFontID change is something that was forgotten in the previous commit about using Ref::INVALID
The change for iccProfileStreamA is only local to that function and has been changed to use Ref::INVALID in all its uses