Unfortunately, the ctype macros follow the current locale in a very inconsistent

Unfortunately, the ctype macros follow the current locale in a very inconsistent
way leading to false positives for isalpha, isalnum, isspace, and isupper for
characters 128-255.  Provide a consistent isfoo implementation that is
restricted to US ASCII for parsing config files and the like.

Drop the PAP backend.

git-svn-id: svn+ssh://src.apple.com/svn/cups/cups.org/trunk@9231 7a7537e8-13f0-0310-91df-b6672ffda945