add .yarnclean, readme update

.yarnclean

@@ -0,0 +1,39 @@
+# test directories
+__tests__
+node_modules/*/test
+node_modules/*/tests
+powered-test
+
+# asset directories
+docs
+doc
+website
+images
+
+# examples
+example
+examples
+
+# code coverage directories
+coverage
+.nyc_output
+
+# build scripts
+Makefile
+Gulpfile.js
+Gruntfile.js
+
+# configs
+.tern-project
+.gitattributes
+.editorconfig
+.*ignore
+.eslintrc
+.jshintrc
+.flowconfig
+.documentup.json
+.yarn-metadata.json
+
+# misc
+*.gz
+*.md

README.md

@@ -13,7 +13,7 @@ Make sure to check out [`electron-webpack`'s documentation](https://webpack.elec
 ## Getting Started
 Simply clone down this reposity, install dependencies, and get started on your application.
 
-The use of the [yarn](https://yarnpkg.com/) package manager is strongly recommended, as opposed to using `npm`.
+The use of the [yarn](https://yarnpkg.com/) package manager is **strongly** recommended, as opposed to using `npm`.
 
 ```bash
 # copy template using curl