Timeout action to execute a build step or a publisher

This adds a timeout action to execute a build step or a publisher. It enables you to send e-mails using the Mailer publisher, for example.

Though this is powerful, it cannot ensure that any build steps can run correct.
So this is provided as an advanced feature, and users need to enable this feature in system configuration page to use.
Issues claiming "Builder XXXXXX does'nt work in timeout action!" will be closed with "Won't Fix".

* System configuration page. This is disabled by default.
    ![systemconfiguration](https://f.cloud.github.com/assets/3115961/2432424/cb60c7a6-ad64-11e3-80ac-08b4293dc466.png)
* You can run a build step in timeout actions.
    ![projectconfiguration](https://f.cloud.github.com/assets/3115961/2432428/e42aeab4-ad64-11e3-8e98-2e5ec4453ba6.png)