cmake - don't print an OK message for each generated file

makes the build a little quieter
neaten up exppp.h
allows exppp output filename (or stdout) to be specified with -o

messages on stdout will corrupt a schema being printed to stdout,
so replace all printf( ... ) and fprintf( stdout, ... ) with
fprintf( stderr, ... )
when a CONSTANT had a long name, no newlines would be printed in initializer lists
-l arg for exppp to set line length
exppp - rename filename buffer
this should not be a warning

libexpress crashes if warnings are suppresed for a schema where this problem occurs
improve pretty-printing of functions