Timer interface has changed

The name of `TimeoutAsyncWork` is now simply `Timer` as of 562d895c234896ad855befd848f6d0f39f8da0db since there used to be a `const TimeoutAsyncWork = Timer` in JuliaLang/julia/base/deprecated.jl but it is now gone.

The julia documentation only mentions `Timer` anyhow.
Merge pull request #81 from domenzain/master

Timer interface has changed