Roll Observatory packages and add a roll script

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

Index: packages/petitparser/lib/src/lisp/cons.dart
diff --git a/petitparser/lib/src/lisp/cons.dart b/packages/petitparser/lib/src/lisp/cons.dart
similarity index 82%
rename from petitparser/lib/src/lisp/cons.dart
rename to packages/petitparser/lib/src/lisp/cons.dart
index bb0463c8086c8e544b89bfb423e10c2ad539d6df..e9fcae7a867559260b735f8560f254ad0a910193 100644
--- a/petitparser/lib/src/lisp/cons.dart
+++ b/packages/petitparser/lib/src/lisp/cons.dart
@@ -1,17 +1,15 @@
-part of lisp;
+part of petitparser.lisp;
 
-/**
- * The basic data structure of LISP.
- */
+/// The basic data structure of LISP.
 class Cons {
 
-  /** The head of the cons. */
+  /// The head of the cons.
   dynamic head;
 
-  /** The tail of the cons. */
+  /// The tail of the cons.
   dynamic tail;
 
-  /** Constructs a cons. */
+  /// Constructs a cons.
   Cons(this.head, this.tail);
 
   @override