Improve ascent

During a "climb", if altitude decreases and accuracy is better

during a "climb", if altitude decreases and accuracy is better# Changes to be committed:
Detect flat sections to improve AscentRate
Bearing and return value for onLocationChanged()
Bugifx: convert bearing in [0-360[
Improve Ascent, Ascent Rate and Save location
Bugfix: detect first location
Bug in _testLocationOKForAscent
bearingText: accept negative values of bearing