When producing PGF, do UTF-8 encoding of the whole file after pretty printing instead of walking through the PGF structure before pretty-printing.

The old code was brittle, and only converted strings in the lins and opers, not in printnames and parsers. The old code also double encoded some grammars when using gfc to combine PGF files.

src/GF/Compile/Export.hs

@@ -58,5 +58,4 @@ outputConcr pgf = case cncnames pgf of
                     cnc:_  -> cnc
 
 printPGF :: PGF -> String
-printPGF = -- encodeUTF8 . -- fromPGF does UTF8 encoding 
-  printTree . fromPGF
+printPGF = encodeUTF8 . printTree . fromPGF