Citymapper, a mapping app that specializes in navigating the complexities of public transportation in big cities, has raised a $10 million Series A round led by Balderton Capital with participation from Connect Ventures, Index Ventures and Greylock Partners. The startup launched as Busmapper in its hometown of London back in 2011, but it’s been layering on other transportation options, from subway lines and trams to ferries and even taxis.