依赖更新 && 构建调整 (#60)

* upgrade dependencies

* 更改所有 saladcss 写法

* fix: 升级依赖导致的样式错误

* fix: build vant css

* use es module when pack && webpack scope hoisting

* fix: vue module version

* delete unused npm script

* fix: build:vant script not work

* fix: webpack config format

* fix: build minify vant.js

* fix: captain ui relative link

packages/vant-css/package.json

@@ -14,13 +14,12 @@
   },
   "license": "MIT",
   "devDependencies": {
-    "autoprefixer": "^6.7.5",
+    "autoprefixer": "^7.1.2",
     "gulp": "^3.9.1",
-    "gulp-cssmin": "^0.1.7",
-    "gulp-postcss": "^6.1.1",
-    "postcss-easy-import": "^2.0.0",
-    "precss": "^1.4.0",
-    "saladcss-bem": "^0.0.1"
+    "gulp-cssmin": "^0.2.0",
+    "gulp-postcss": "^7.0.0",
+    "postcss-easy-import": "^2.1.0",
+    "precss": "^2.0.0"
   },
   "dependencies": {}
 }