[Build] extract build iconfont (#1242)

build/get-components.js

@@ -0,0 +1,8 @@
+const fs = require('fs');
+const path = require('path');
+
+module.exports = function() {
+  const dirs = fs.readdirSync(path.resolve(__dirname, '../packages'));
+  const excludes = ['index.js', 'vant-css', 'mixins', 'utils', '.DS_Store'];
+  return dirs.filter(dirName => excludes.indexOf(dirName) === -1);
+};