convert AST_Seq from binary tree to array (#1460)

- rename `AST_Seq` to `AST_Sequence`
- raise default sequences_limit from 200 to 800

lib/mozilla-ast.js

@@ -149,7 +149,11 @@
             });
         },
         SequenceExpression: function(M) {
-            return AST_Seq.from_array(M.expressions.map(from_moz));
+            return new AST_Sequence({
+                start      : my_start_token(M),
+                end        : my_end_token(M),
+                expressions: M.expressions.map(from_moz)
+            });
         },
         MemberExpression: function(M) {
             return new (M.computed ? AST_Sub : AST_Dot)({
@@ -332,10 +336,10 @@
         };
     });
 
-    def_to_moz(AST_Seq, function To_Moz_SequenceExpression(M) {
+    def_to_moz(AST_Sequence, function To_Moz_SequenceExpression(M) {
         return {
             type: "SequenceExpression",
-            expressions: M.to_array().map(to_moz)
+            expressions: M.expressions.map(to_moz)
         };
     });