Add timeout acquiring from pool

[mpaolini]

Stab at issue #16

TODO:

• tests

[jettify]

asyncio usually do not pass timeout as kw argument in favour wait and wait_for, I think we should follow aiohttp:

with aiohttp.Timeout(0.001):
    async with aiohttp.get('https://github.com') as r:
        await r.text()

this context manager is present in new asyncio and packaged with aiohttp.

[mpaolini]

so you are suggesting we close #16 ?

[asvetlov]

Unfortunately asyncio.timeout was ripped out from asyncio due problems with tornado.
aiohttp.Timeout is working and will present for very long time.

So yes, I suggest using timeout context manager and don't add timeout parameter.