Add `.npmignore` to ignore `src`

.npmignore

@@ -0,0 +1,42 @@
+# OSX
+.DS_Store
+
+# Node.js
+
+# ignore src files
+src
+
+# Logs
+logs
+*.log
+npm-debug.log*
+
+# Runtime data
+pids
+*.pid
+*.seed
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directory
+# https://docs.npmjs.com/misc/faq#should-i-check-my-node-modules-folder-into-git
+node_modules
+
+# IntelliJ project files
+.idea
+*.iml
+out
+gen