Document ExpectTimeout()

[FrankReh]

Reading the documentation and the test cases led me to believe there was no handling for the case of a timeout. But then I looked at your actual code and you do use the time.After() inside a select go idiom for a timeout option. Why not provide an example in your read me, or provide a test case?

This looks iike a very promising project. I wrote a ton of expect a long time ago and now that I'm into go, having a go version of expect is great. Amazing how few lines of go it takes to make something so useful.

Also, why not make the timeout error a global constant so the user could test the error received against it to handle the normal timeout case more cleanly?