Merge pull request #1535 from serhii-londar/2.6.8

2.6.8

Author: TimSylvester

ios/library/WhirlyGlobe-MaplyComponent/src/MaplySphericalQuadEarthWithTexGroup.mm

@@ -52,7 +52,7 @@ - (bool)startLayer:(WhirlyKitLayerThread *)layerThread scene:(WhirlyKit::Scene *
 
     earthLayer = [[WhirlyKitSphericalEarthQuadLayer alloc] initWithInfo:texGroupName renderer:renderer];
     if (!earthLayer)
-        return nil;
+        return false;
     [layerThread addLayer:earthLayer];
 
     return true;