Add MyLocation to compute statistics on filtered gps data

Example:
 _myLocation.getAverageSpeed(); // in m/s
 _myLocation.getDistance(); // in m
 _myLocation.getElapsedTime() // in ms
 _myLocation.getAltitude() // in m
 _myLocation.getAscent() // in m
Bugfix: intial value of lastGoodAscentLocation
Merge pull request #1 from jay3/master

GPS data filtering + stats