A little bug with line thickness

[gerchicov]

Function OpenGLPath::buildFatLineSegment(...) in glPath.cpp:

One of parameters has name "radius" abd you pass stroke_width into it. But stroke_width look likes as diameter.
And of course all the lines looks too fat.

[gerchicov]

additionally if I change them to a real size then lines could disappear because app view always thinks that it is displayed in non-retina display.