In general it's easier to implement and should have more predictable performance
semantics for applications in general. More serious timer usage can go through
`tokio-timer` which has properly configurable timer wheels and such.
Closes#2Closes#7
* Handle -> Remote
* Pinned -> Handle
All APIs now take a `&Handle` by default and in general can return an immediate
`io::Result` instead of an `IoFuture`. This reflects how most usage will likely
be done through handles rather than remotes, and also all previous functionality
can be recovered with a `oneshot` plus `Remote::spawn`.
Closes#15