Roll Observatory packages and add a roll script

packages/petitparser/lib/src/lisp/grammar.dart

-part of lisp;
+part of petitparser.lisp;
 
-/**
- * LISP grammar.
- */
+/// LISP grammar.
 class LispGrammar extends GrammarParser {
   LispGrammar() : super(new LispGrammarDefinition());
 }
 
-/**
- * LISP grammar definition.
- */
+/// LISP grammar definition.
 class LispGrammarDefinition extends GrammarDefinition {
 
   start() => ref(atom).star().end();
 
   atom() => ref(atom_).trim(ref(space));
   atom_() => ref(list)
       | ref(number)
       | ref(string)
       | ref(symbol)
       | ref(quote)
@@ skipping 27 matching lines @@
   quote() => char('\'') & ref(list);
   quasiquote() => char('`') & ref(list);
   unquote() => char(',') & ref(list);
   splice() => char('@') & ref(list);
 
   space() => whitespace() | ref(comment);
   comment() => char(';') & Token.newlineParser().neg().star();
   bracket(String brackets, Parser parser) => char(brackets[0]) & parser & char(brackets[1]);
 
 }