message: fix umd bundle build
diff: const webpack = require('webpack');
  +var util = require('./util');
  module.exports = {
  entry: './src/lib/components/index.ts',
  output: {
  - path: './dist/bundle',
  + path: util.root('dist/bundle'),
  filename: 'core.js',
  libraryTarget: 'umd',
  library: 'angularMdlCore'
  