Rework command-line option parsing to enable default values
Rework command-line option parsing to enable default values

Change-Id: I3e53f38e6f242351c0f41b85fbad534c00663f9e
Reviewed-on: https://dart-review.googlesource.com/39982
Reviewed-by: Jens Johansen <05223a3c6bdf76af6f84755eae231abeebcf4530@google.com>
Commit-Queue: Peter von der Ahé <ad40f903ca639ca334d95dc5a5f0ae92bd708079@google.com>

dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk