grammar.py and friends: Make list parsing run through

First time parsing doesn't error out with a syntax error. No usable AST
is produced, strings are not returned from lexer, and AST lists aren't
lists, really.

TEXT:="Hello world!"; had to be excluded from the example, because I
don't get how this could be parsed with the given syntax. There's a
special sequence "all visible characters", but any lexer regex I could
think of will also match the types defining "alphabetic character" and
return the respective tokens (e.g. T_A) or vice-versa, depending on the
order in the lexer input file. I suppose, the only sensible way to
handle this, is to define "all visible characters" by defining the
tokens for the missing characters, and then use them along T_A ... T_Z
or their derived types.

Signed-off-by: Jan Lindemann <jan@janware.com>

test/grammar/grammartest-input.ebnf

@@ -2,7 +2,7 @@
  program = 'PROGRAM', white space, identifier, white space, 
             'BEGIN', white space, 
             { assignment, ";", white space }, 
-            'END.' ;
+            'END.', [ white space ];
  identifier = alphabetic character, { alphabetic character | digit } ;
  number = [ "-" ], digit, { digit } ;
  string = '"' , { all characters }, '"' ;