add all changes since release

This commit contains all changes to our online version since the
initial release of v1.5.

* ADD: importer for sml-files
* FIX: use newest api of OpenWeatherMap
* FIX: use username for geonames.org
* FIX: bug in rounds view with other units than "min/km"
* FIX: some minor bugs
* CHANGE: minor performance improvements
* CHANGE: links to GitHub instead of Trac