legends are not displayed

[Joern Ungermann]

Some WMS servers offer a separate legend graphics. The relevant code is not covered by the unit tests as our WMS server does not support this feature. The code retrieving the graphics was changed for the Py3 conversion according to documentation but the legend is not displayed anymore.

Server with legends: http://osmwms.itc-halle.de/maps/osmfree

[Reimar Bauer]

Bug fix for display of legends.

Division had, surprisingly, float arguments.

Fixes issue #192

→ <<cset 68f4d9d8112a>>