Disable gradients by default. Fixes #150.

lib/pages/mandala-page/mandala-design.avsc.json

@@ -33,7 +33,7 @@
           { "name": "fill", "type": "int" },
           { "name": "background", "type": "int" },
           { "name": "uniformStrokeWidth", "type": "float" },
-          { "name": "disableGradients", "type": "boolean", "default": false }
+          { "name": "disableGradients", "type": "boolean", "default": true }
         ]
       }
     },

lib/pages/mandala-page/serialization.test.ts

@@ -24,7 +24,7 @@ describe("Mandala design serialization/desrialization", () => {
     const design = decodeAndDeserialize(
       "AgZleWUAAB9DCAEAAIA%2FAAAAAAAAgD8AAAAAAADQlAKCjj3Ij%2F4PAACAPwAAQEABAA%3D%3D"
     );
-    expect(design.baseCompCtx.disableGradients).toBe(false);
+    expect(design.baseCompCtx.disableGradients).toBe(true);
     expect(design.circle1.numSymbols).toBe(4);
   });
 

lib/svg-symbol.tsx

@@ -104,7 +104,7 @@ const DEFAULT_CONTEXT: SvgSymbolContext = {
   fill: "#ffffff",
   showSpecs: false,
   uniformStrokeWidth: DEFAULT_UNIFORM_STROKE_WIDTH,
-  disableGradients: false,
+  disableGradients: true,
 };
 
 /**