modified:   PoIInterface/PoIInterface/Data/FwCore.cs
fixed an error while reading descriptions

	modified:   PoIInterface/PoIInterface/PoIInterface.cs
RadialSearch can filter by category, Add returns the newly created poi (so no ref parameter is required anymore)

	modified:   PoIInterface/PoIInterface/Requests/RadialSearchRequest.cs

	new file:   PoIInterface/PoIInterfaceTestApp/Data/overpass_bus_stops_barcelona.json
	new file:   PoIInterface/PoIInterfaceTestApp/Data/overpass_bus_stops_switzerland.json

	modified:   PoIInterface/PoIInterfaceTests/TestPoI.cs
Updated tests for AddPoi