Delete proxy and total samples, which have bit-rotted.

samples/total/client/Exceptions.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-interface TotalException {
-  String toString();
-}
-
-class FormulaException implements TotalException {
-  final String _message;
-
-  // when Dart supports optional args, message will be optional
-  const FormulaException(String this._message);
-
-  String toString() => _message;
-}
-
-class BadFormulaException extends FormulaException {
-  const BadFormulaException() : super("#BADFORMULA!");
-}
-
-class CycleException extends FormulaException {
-  const CycleException() : super("#CYCLE!");
-}
-
-class DivByZeroException extends FormulaException {
-  const DivByZeroException() : super("#DIV/0!");
-}
-
-class FunctionException extends FormulaException {
-  const FunctionException() : super("#FUNC!");
-}
-
-class NumArgsException extends FormulaException {
-  const NumArgsException() : super("#NARGS!");
-}
-
-class NumberException extends FormulaException {
-  const NumberException() : super("#NUM!");
-}
-
-class RefException extends FormulaException {
-  const RefException() : super("#REF!");
-}
-
-class ValueException extends FormulaException {
-  const ValueException() : super("#VALUE!");
-}
-
-class RuntimeException implements TotalException {
-  final String _message;
-
-  // when Dart supports optional args, message will be optional
-  const RuntimeException(String this._message);
-
-  String toString() => _message;
-}