Updated Docker::Container#wait to accept an optional number of seconds.

Timeouts were occurring when a command lasted for more than 60 seconds.
Rather than hardcoding an unreasonable number in, 60 is now the default.
Lowered the cane abc-max well below the default.

An abc-complexity of 12 was the worst that we have right now. The idea
is if any methods become more complex that `Docker::Image.import`, I'd
like the build to fail.
Version bump 1.1.2
Badges for dependencies and gem version
Added Docker::Error::TimeoutError.
Merge pull request #15 from swipely/improve-container-wait

Improve container wait