create an ergnonmic sync api

[xmclark]

I'm fond of node.js's strategy for sync and async APIs. They maintain two copies of a function: one that is sync and one that is not (async). I have not seen this pattern in Rust, but I'm sure it could be ported.

This allows a user to not worry about futures, runtime or "wait"ing. A lot of times, you just want to block, especially for simpler apps.