2D Trilateration

Simple 2D trilateration algorithm with Google Earth output example.

From :
- coordinates of 3 references points,
- distance of an unknown point to the references points,
Return : coordinates of the unknown point.
A study example is furnished with output to Google Earth kml file.
The credits to the original trilateration code should be given to http://gis.stackexchange.com/questions/66/trilateration-using-3-latitude-and-longitude-points-and-3-distances (cmeeren - 28/07/2010).
The study was done for a Wifi Positionning System (3 Access Point; 1 Mobile Station).