Issue 731: Add new docker template option for container stop timeout

[sithmein]

Addresses #731 .

[sithmein]

The test failures are very likely not caused by the PR since the same tests have also been failing for the latest commit on master.
I cannot run them locally, too, especially DockerComputerSSHConnectorTest always times out.

[pjdarton]

Thanks for the PR.
I'm a bit snowed-under at work to deal with this right now (and going on vacation tomorrow for a week) so this isn't going to get merged immediately, but once I'm "back in the game" I'll take a detailed look and take it from there.
In the meantime, if you could "persuade" the JenkinsCI system to do a non-broken build, that would be good. FYI if you close the PR, wait 10-15 minutes (for the JenkinsCI system to notice it's gone), and then re-open the PR (i.e. re-open the old PR; don't create a new one) then the JenkinsCI system should have another try at building it.
If it's consistently borked, bring it to the attention of Jenkins folks on IRC e.g. http://webchat.freenode.net/?channels=jenkins-infra

Re: Can't run unit-tests locally
I used to have that problem too - until I updated docker on my test system. There's nothing special about the build environment that the JenkinsCI systems have so you should be able to run the build & tests locally.

[pjdarton]

I'm going to close this PR, wait a bit, and re-open it to try to get the Jenkins CI build to rebuild it - hopefully it'll build cleanly...

[pjdarton]

This code would benefit from declaring a int constant of 10 to hold the default timeout, and then reference that everywhere.
If we can't manage to reference it "everywhere" then every declaration of 10 seconds needs a comment (aimed at any future maintainers of this code) saying where else it's defined and the importance of keeping them in step.
At present, we've got it being defaulted to 10 seconds in multiple places but 100 in another - we need to fix that and make that kind of mistake harder to make.

Aside from that, the code changes are nice and neat 😀