Add expectAsyncX and expectAsyncUntilX methods, and deprecate the old methods.

CHANGELOG.md

Index: CHANGELOG.md
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 56507bd3fb78581d1b0621d9b13bfb4b8360a9c5..d68eacaf1227457d801169065678c0adeae22343 100644
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@@ -1,3 +1,10 @@
+## 0.13.0
+
+* Deprecated `expectAsync` and `expectAsyncUntil`, to make the package strong
+  mode clean. Replaced by
+    * `expectAsync0`, `expectAsync1`, ... `expectAsync6`, and
+    * `expectAsyncUntil0`, `expectAsyncUntil1`, ... `expectAsyncUntil6`.

[nweiz, 2016/11/21 22:08:02]

It would be nice to have more details here. I'd write:

"Deprecate `expectAsync()` and `expectAsyncUntil()`, since they currently can't
be made to work cleanly in strong mode. They're replaced with separate methods
for each number of callback arguments:"

[floitsch, 2016/11/22 14:14:27]

Done.

+
 ## 0.12.16
 
 * Allow tools to interact with browser debuggers using the JSON reporter.