Fixed volume background color in viewParams api

docs/methods.md

@@ -252,6 +252,6 @@ The request/response payload is a JSON object containing view parameters:
                 //   2 - Slice clipping (Sample only the plane intersection slice)
     "planeCenter": [xDim/2,yDim/2,zDim/2], // Sample plane location in image coordinates. NOTE: this is a point on the plane, the plane orientation is determined by the view direction (worldRot).
     "bgColor": [0.4,0.4,0.4,1], // Canvas background color (including alpha)
-    "volColor": [0,0,0,1], // Volume background color
+    "volColor": [0,0,0], // Volume background color
 }
 ```