Got rid of last vestiges of unsigned char * code for I18N - sticking with

Got rid of last vestiges of unsigned char * code for I18N - sticking with
plain char because we don't do any comparisons and each compiler gives
different warnings/errors...

ippRead() didn't employ a blocking read for each variable read, which caused
problems under some circumstances.

ppdOpenFile() didn't handle buggy PPD files that declared VariablePaperSize
false and still had CustomPageSize commands...

Added password authorization handling to cupsDoRequest() - automatically
asks for a password (from the console) if one is needed.  [Note: the GUIs
will need to implement their own version of this.]

git-svn-id: svn+ssh://src.apple.com/svn/cups/cups.org/trunk@229 7a7537e8-13f0-0310-91df-b6672ffda945