Support for multijob: phases as lanes and status for current build

[lpenz]

The multijob integration is working as follows:

• you should order the jobs by phase (new order plugin)
• when "multijobLanes" is selected in the settings, the "columns" slider disappears, and the jobs will then have a width of 100% / jobs in that phase for the parent multijob
• you should not mix jobs from different multijobs projects, as they will be mixed up in the view
• when a new multijob run starts, the view is smart enough to show only the job status for that multijob run (thanks @Brantone for Grouping: Support for MultiJob grouping #98)

Functionally, this implementation looks exactly as I though it should.
I'm do not think it is good enough from a code perspective. I was not able to add any tests, and I think I might be adding an unwanted dependency in some points. Do you have any pointers on that?

[jan-molak]

Many thanks for your contribution @lpenz , I'll review it as soon as I'm done with the performance issue mentioned in #151