[FIXED JENKINS-20164] Use dropdown for strategy instead of hetero-radio, as it can conflicts with other plugins. Upgraded target Jenkins version as rendering an expanded help requires layoutUpdateCallback introduced in Jenkins 1.452.
[JENKINS-20164] Explicitly make AbsoluteTimeOutStrategy default.
Merge pull request #27 from ikedam/feature/JENKINS-20164_strategyRadioToDropdown

[JENKINS-20164] Use dropdown for strategy instead of hetero-radio