Can't calculate middleness when street segments don't represent the whole street well

[nch0w]

Here is a label:

The program found this closest segment:

The proximity returned was (dist, percentage) = (10.147059502276088, 92.7984294326395). It's correct that the distance is ~10m, but the percentage should be close to 0%, since the label is really close to an intersection.

[nch0w]

@jonfroehlich I will open a pull request from https://github.com/nchowder/label-intersection-proximity when the street network issue is fixed.