Roll Observatory packages and add a roll script

packages/petitparser/lib/src/reflection/optimize.dart

-part of reflection;
+part of petitparser.reflection;
 
-/**
- * Returns a copy of [parser] with all settable parsers removed.
- */
+/// Returns a copy of [parser] with all settable parsers removed.
 Parser removeSettables(Parser parser) {
   return transformParser(parser, (each) {
     while (each is SettableParser) {
       each = each.children.first;
     }
     return each;
   });
 }
 
-/**
- * Returns a copy of [parser] with all duplicates parsers collapsed.
- */
+/// Returns a copy of [parser] with all duplicates parsers collapsed.
 Parser removeDuplicates(Parser parser) {
   var uniques = new Set();
   return transformParser(parser, (source) {
     var target = uniques.firstWhere((each) {
       return source != each && source.isEqualTo(each);
     }, orElse: () => null);
     if (target == null) {
       uniques.add(source);
       return source;
     } else {
       return target;
     }
   });
 }