New timeout handling to fix issue #52

[dterei]

Few different people reported issue #52, this commit fixes it.

Basically what would occur is if you ran the following:

for (i = 0; i < 20; i++) {
    mc.set('key', 'value');
}

You'd get an exception as Node doesn't like you creating more than 11 timeouts by default, and we'd try to create 20. We could increase the number of timeouts allowed (to infinite), but this design seems nicer, to just use one timeout and track deadlines in a queue.

We also bump to version 0.9.2.

[alevy]

This seems fine, but because it changes a pretty core part of the request handling, maybe it's best to bump to 0.10 instead? It looks pretty solid and seems well tested, but the current timeout handling was the result of some pretty gnarly edge cases that came up in deployment.

[dterei]

Sure, happy to bump to 0.10.