Parse comma-separated multiple values.

README.md

Index: README.md
diff --git a/README.md b/README.md
index fa635cb4eb7686783642b963f99892947b9d27c8..8d8cb3099211dfc76a9ea8194b258aad80bb5ee4 100644
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+++ b/README.md
@@ -189,6 +189,17 @@ var results = parser.parse(['--mode', 'on', '--mode', 'off']);
 print(results['mode']); // prints '[on, off]'
 ```
 
+By default, multiple options' values may also be separated with commas:

[Bob Nystrom, 2015/03/04 22:01:37]

This reads a bit ambiguously to me (it could mean multiple different options).
How about: "values for a multi-valued option"?

[nweiz, 2015/03/04 22:05:41]

Done.

+
+```dart
+var parser = new ArgParser();
+parser.addOption('mode', allowMultiple: true);
+var results = parser.parse(['--mode', 'on,off']);
+print(results['mode']); // prints '[on, off]'
+```
+
+This can be disabled by passing `splitCommas: false`.
+
 ## Defining commands ##
 
 In addition to *options*, you can also define *commands*. A command is a named