Added a static class for implementation of #12.
Implemented the second signature (parameterized) as described in #12.
Merge branch 'master' into immobile-bikes-#12

Conflicts:
	CityBikes/Library/Library.csproj
Created a method in GPSLocation that determines the distance between two locations.
Implemented GetBikesImmobilem such that the most-recent data is returned for each bike.
Documented the last method in BikeStandstill.
Moved the inVicinity method to the gps_data class.
Renamed gps_data.inVicinity -> gps_data.WithinAccuracy.
Added documentation for the methods defined in the gps_data class.
Added test method for BikeStandstill.
Merge branch 'master' of github.com:sw701/code