Corrupted PDF Fix

* Added check for corrupt PDFs when outputting the "_SPEC" PDF.
* Bumped version number up to v2.54.
Further refinements and fixes.

Proof:
* Set drink stirrers and food piks to automatically be set as 4CP jobs
in the 2nd Proofing dialog.
* When deleting files during a replacement, made sure to delete "_SPEC"
files as well.
* Moved the "Unlocking Cover Sheet" progress text to display only once
ALL items have been processed.
* Bumped version number up to v2.55.

Output:
* Stopped outputting colors that are set as DEBOSS or EMBOSS.