Add simple implementation of power-lines

This is an inefficient way of detecting whether a group
of powerlines (which will be sent by openCV as a single
contour group) touches both a village and a windfarm. If
it does, then it assumes that power is being delivered to
village.

The shapes-client is updated as well, now sending only
red non-polygons, which are interpreted as powerlines.

Next, we need to group our individual calibrations and
find them all independently.
Send calibration data for each item to OpenCV

Now OpenCV can pick out individual contours with different
calibrations, and send them back to the browser with
named groups.