Allow for customisation of Travis build status output

[madmatt]

For dashboards that display a lot of repos (e.g. 70+), listing all fully-green repos takes a lot of screen space. Additionally, listing green branches on a failing build takes a lot of space too - if there's only one failing branch that's the only thing you're really interested in at a glance.

It would be cool to be able to adjust these - or perhaps split the current view into two - one for failing Travis builds that displays like the current one, and one that is just a single number that indicates the number of completely passing repos for all branches.