Minor correction to getAngle.
Always use c2 to calculate the initial bearing. 
(c1.bearingTo(c2) != c2.bearingTo(c1) - 180)
The previous version returned wrong values
when the distance between c1 and c2 or c2 and c3 
was large.
See http://www.movable-type.co.uk/scripts/latlong.html


git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@2795 25d90789-57f7-4ee0-8453-03a3dfeeeb22