improvements

Better handling for multiple usage of same job in one multijob project.
Bug fix in build view when same job run simultaneously in few multijob projects.
Failure of one job will not cancel immediately other jobs in same phase but will let finish the run of the phase and then will cancel the multijob. Probably a temporary solution, at least until possibility to configure it for each job in phase.
Small ui improvements.
"Failure" - continuation condition to next phase added.
Job configuration added to "kill" phase on selected job statuses. 
Job configuration added to disable execution of selected job. 
More ui  improvements.
Back to CopyOnWriteArrayList structure of build status store, for backward compatibility reasons.