[BUG] Providing domain with negative start value causes NPE

[corneil]

Describe the bug

I am plotting geoPoints on a geoMap

When I get min and max for the column used to determine the geoPoint size and provide this range as the domain and the min is negative for the scale I experience the following:

java.lang.NullPointerException: null
	at org.jetbrains.letsPlot.core.plot.base.aes.AesScaling.strokeWidth(AesScaling.kt:18)
	at org.jetbrains.letsPlot.core.plot.base.geom.util.LinesHelper$decorate$1.invoke(LinesHelper.kt:228)
	at org.jetbrains.letsPlot.core.plot.base.geom.util.LinesHelper.decorate(LinesHelper.kt:241)
	at org.jetbrains.letsPlot.core.plot.base.geom.PolygonGeom.buildIntern(PolygonGeom.kt:33)

The plot as follows:

plot {
    withData(overviewGeoMap) {
         geoMap {
	    fillColor(countryCode) {
              legend.name = "Country Code"
              alpha = 0.7
              scale = categorical("USA" to Color.BLUE, "CAN" to Color.RED,"MEX" to Color.GREEN)
            }
            borderLine.color = Color.BLACK
            borderLine.width = 0.1
        }
    }
    withData(dataGeoPlot) {
       geoPoints {
           color(focusAreaColourColumn) {
               scale = continuous(Color.GREEN..Color.RED, domain = minColourValue..maxColourValue)
           }
           legend.name = messageSource.getMessageText(locale, focusAreaColourColumn.name())
           size(focusAreaSizeColumn) {
               scale = continuous(range = 3.0..12.0, domain = minSizeValue..maxSizeValue)
               legend.name = messageSource.getMessageText(locale, focusAreaSizeColumn.name())
           }				
       }
    }
    withData(level1Names) {
        text {
          label(level1Name)
	  alpha = 1.0
	  x(centerX)
	  y(centerY)
	  font.color = Color.BLACK
	  font.size = 6.0
	  font.family = FontFamily.SANS
       }
    }
}

When I remove the domain = to the continuous() scale the NPE doesn't occur.