update scales test case, remove unused dev dependency

package.json

@@ -65,7 +65,6 @@
     "rollup-plugin-node-resolve": "5",
     "rollup-plugin-uglify": "6",
     "rollup-pluginutils": "2",
-    "rollup-watch": "4",
     "selenium-webdriver": "3",
     "tap-merge": "0.3",
     "tape": "4",

rollup.config.js

@@ -6,7 +6,7 @@ import babel from 'rollup-plugin-babel'
 import babelrc from 'babelrc-rollup'
 
 const babelConfig = {
-  'presets': ['es2015']
+  presets: ['es2015']
 }
 
 export default [
@@ -162,7 +162,7 @@ export default [
       commonjs(),
       babel(babelrc({
         config: {
-          'presets': ['env']
+          presets: ['env']
         }, exclude: 'node_modules/**' })),
       process.env.npm_lifecycle_event == 'dev' ? '' : uglify({ sourcemap: true })
     ],

test/test-scale.html

@@ -290,13 +290,14 @@
         scale: 'Quantize',
         range: { scheme: 'Purples', count: 3 }
       })
-      // 0 - 33
+      // min_number is probably close to 0, max_number is probably close to 100
+      // [min_number, min_number + (min_number+difference)/3]
       t.equal(quantize_scale(15), d3.schemePurples[3][0])
       t.equal(quantize_scale(25), d3.schemePurples[3][0])
-      // 33.3 - 66
+      // [ min_number + (min_number+difference)/3, min_number + 2*(min_number+difference)/3]
       t.equal(quantize_scale(40), d3.schemePurples[3][1])
-      t.equal(quantize_scale(65), d3.schemePurples[3][1])
-      // 66 - 100
+      t.equal(quantize_scale(45), d3.schemePurples[3][1])
+      // [2*(min_number+difference)/3, max_number]
       t.equal(quantize_scale(70), d3.schemePurples[3][2])
 
 
@@ -310,13 +311,14 @@
           reverse: true
         }
       })
-      // 0 - 33
+      // min_number is probably close to 0, max_number is probably close to 100
+      // [min_number, min_number + (min_number+difference)/3]
       t.equal(quantize_scale(15), d3.schemePurples[3][2])
       t.equal(quantize_scale(25), d3.schemePurples[3][2])
-      // 33.3 - 66
+      // [ min_number + (min_number+difference)/3, min_number + 2*(min_number+difference)/3]
       t.equal(quantize_scale(40), d3.schemePurples[3][1])
       t.equal(quantize_scale(65), d3.schemePurples[3][1])
-      // 66 - 100
+      // [2*(min_number+difference)/3, max_number]
       t.equal(quantize_scale(70), d3.schemePurples[3][0])