Move a bunch of src/ files into subdirectories.

lib/src/exit_codes.dart

Index: lib/src/exit_codes.dart
diff --git a/lib/src/exit_codes.dart b/lib/src/exit_codes.dart
deleted file mode 100644
index ce39d1e31f2548cf719d45ae2728404562fb9db7..0000000000000000000000000000000000000000
--- a/lib/src/exit_codes.dart
+++ /dev/null
@@ -1,58 +0,0 @@
-// Copyright (c) 2015, 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.
-
-/// Exit code constants.
-///
-/// From [the BSD sysexits manpage][manpage]. Not every constant here is used.
-///
-/// [manpage]: http://www.freebsd.org/cgi/man.cgi?query=sysexits
-library unittest.exit_codes;
-
-/// The command completely successfully.
-const success = 0;
-
-/// The command was used incorrectly.
-const usage = 64;
-
-/// The input data was incorrect.
-const data = 65;
-
-/// An input file did not exist or was unreadable.
-const noInput = 66;
-
-/// The user specified did not exist.
-const noUser = 67;
-
-/// The host specified did not exist.
-const noHost = 68;
-
-/// A service is unavailable.
-const unavailable = 69;
-
-/// An internal software error has been detected.
-const software = 70;
-
-/// An operating system error has been detected.
-const os = 71;
-
-/// Some system file did not exist or was unreadable.
-const osFile = 72;
-
-/// A user-specified output file cannot be created.
-const cantCreate = 73;
-
-/// An error occurred while doing I/O on some file.
-const io = 74;
-
-/// Temporary failure, indicating something that is not really an error.
-const tempFail = 75;
-
-/// The remote system returned something invalid during a protocol exchange.
-const protocol = 76;
-
-/// The user did not have sufficient permissions.
-const noPerm = 77;
-
-/// Something was unconfigured or mis-configured.
-const config = 78;