allow "-" hyphen as an option argument with subcommand

index.js

@@ -737,7 +737,7 @@ Command.prototype.parseOptions = function(argv) {
       // If the next argument looks like it might be
       // an argument for this option, we pass it on.
       // If it isn't, then it'll simply be ignored
-      if (argv[i+1] && '-' != argv[i+1][0]) {
+      if (argv[i+1] && ('-' != argv[i+1][0] || '-' === argv[i+1])) {
         unknownOptions.push(argv[++i]);
       }
       continue;

test/test.options.subcommand-hyphen.js

@@ -0,0 +1,21 @@
+/**
+ * Module dependencies.
+ */
+
+var program = require('../')
+    , should = require('should');
+
+program
+    .command('subcommand')
+    .description('description')
+    .option('-a, --alpha <a>', 'hyphen')
+    .option('-b, --bravo <b>', 'hyphen')
+    .option('-c, --charlie <c>', 'hyphen')
+    .action(function (options) {
+    });
+
+program.parse('node test subcommand -a - --bravo - --charlie=-'.split(' '));
+
+program.commands[0].alpha.should.equal('-');
+program.commands[0].bravo.should.equal('-');
+program.commands[0].charlie.should.equal('-');