added a nil check when creating a MultiPolyline
fixed a potential bug
import GPX URLs by opening an URL with the scheme "tracktivity" (e.g. tracktivity://localhost/maps/track.gpx)
trying to fix location manager usage in background when not needed
added default title to detail view
tested some line widths
renamed app
added sharing panel
use an action sheet to open activity in safari
create tracktivity URL in getter
use a recorded track as background track (not drawn into map yet)
added custom UIActivity to open URL in Safari (iOS 6 only)
re-added accidentally deleted strings
display background track in record view (needs a different color/opacity; should be removable)
removed obsolete class
use a different color/opacity for background tracks
improved distance filter for encoded polylines
further improved distance filter for encoded polylines
do not check path extension when importing gpx files via url
open imported route using the notification center