fix (carousel): carousel width was incorrectly rounded

Rounding the carousel width caused display bugs in case where parent
containers did not have round widths, like a fluid column in a bootstrap
guide. The resulting width produced unexplained 1px margin, and a slight
shift from slide to slide.
Merge pull request #136 from ActivKonnect/feature/fix_container_width

fix (carousel): carousel width was incorrectly rounded