Roll Observatory packages and add a roll script

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

-part of lisp;
+part of petitparser.lisp;
 
-/**
- * LISP parser.
- */
+/// LISP parser.
 class LispParser extends GrammarParser {
   LispParser() : super(new LispParserDefinition());
 }
 
-/**
- * LISP parser definition.
- */
+/// LISP parser definition.
 class LispParserDefinition extends LispGrammarDefinition {
 
   list() => super.list().map((each) => each[1]);
 
   cell() => super.cell().map((each) => new Cons(each[0], each[1]));
   empty() => super.empty().map((each) => null);
 
   string() => super.string().map((each) => new String.fromCharCodes(each[1]));
   characterEscape() => super.characterEscape().map((each) => each[1].codeUnitAt(0));
   characterRaw() => super.characterRaw().map((each) => each.codeUnitAt(0));
 
   symbol() => super.symbol().map((each) => new Name(each));
   number() => super.number().map((each) {
     var floating = double.parse(each);
     var integral = floating.toInt();
     if (floating == integral && each.indexOf('.') == -1) {
       return integral;
     } else {
       return floating;
     }
   });
 
   quote() => super.quote().map((each) => new Cons(Natives._quote, each[1]));
 
 }