Update debug2 log messages to use function name prefix and debug

Update debug2 log messages to use function name prefix and debug
and higher to not use function names.

Add printer-specific document-format-supported attributes.

scheduler/printers.c:
    - cupsdAddPrinterFilter(): Renamed to static add_printer_filter().
    - cupsdCreateCommonData(): Remove document-format-supported.
    - cupsdSetPrinterAttrs(): Call add_printer_formats() for printer-
      specific formats.
    - add_printer_formats(): Added.

git-svn-id: svn+ssh://src.apple.com/svn/cups/cups.org/trunk@5083 7a7537e8-13f0-0310-91df-b6672ffda945