Add example for idle_timeout docs

[karlhorky]

Ref #119

[porsager]

Cool.. Should be idle_timeout though ;)

[karlhorky]

Oh, oops, bad copy+paste! Fixed.

[mishanti]

Please update the readme to include that idle_timeout was renamed to timeout, thanks!

[porsager]

It's the other way around. Note that github master is v2 which is available on npm as npm i postgres@beta currently. You can find the v1 docs here http://npmjs.com/postgres or here https://github.com/porsager/postgres/tree/v1 (which has timeout correctly for v1).