Don't show() in buildCarousel

Show stuff is the controller's responsibility.

NOTE: This is a breaking change if you're not calling
`controller.start()` or `controller.show()` somewhere in your
initializing code.

This should fix finn-no/carousel-js#20.
Update examples to use controller.start()
Merge pull request #21 from msolli/indexOneBugfix

Don't show() in buildCarousel