measurement plugin inconsistencies of selections with nodes and ways

[dieterdreist]

There is some inconsistency in the measurement plugin: if you draw a square with 100m length of its side, and select the way the selection length is displayed as 400 meters. When you now select the nodes of the sides as well, the selection length is 700 meters.

Another issue seems to be the displayed are: the selection area of the above square 100x100 is 9582.26 m². When moving the "square" to the south until the area is displayed as 10000.00 m² the displayed selection lenght of the way is 408.42 m

Btw: The displayed "path length" is always 0.