StrokeWidth doesn't work for GeoJsonDataSource

[lydart]

Step to reproduce:

1. go to https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/?src=GeoJSON%20and%20TopoJSON.html&label=DataSources
2. For Basic styling, edit strokeWidth to 30
3. Run

Expected - Line width should be wider
Actual - Line width didn't change

[mramato]

@lydart this is a limitation of Windows browsers (it works on Linux, Android, iOS, and Mac), see https://stackoverflow.com/a/25405483/3191039 for full details. Basically the maximum limit is whatever viewer.scene.maximumAliasedLineWidth reports.

The good news is that we have an alternate implementation that would allow this, but no exact ETA on when it will be in. Keep your eye on #6694.