provide predictable function signatures

[rodneyrehm]

The methods execute() and waitFor() (amongst other methods to come) accept functions to be executed in the browser context.

While one method may actually do something different, from a caller's perspective they look far too similar to allow them different signatures:

execute(func, arg1, arg2, arg3);
waitfor(func, [arg1, arg2, arg3], timeout)

Pick one style and stick with it.