Add option to watch for changes on other files in the project about webpack-livereload-plugin

[hirasso]

@statianzo
extra-watch-webpack-plugin can indeed watch my php files and re-compile if I save them, but it doesn't trigger your livereload script to reload my browser.

[statianzo]

@hirasso
Would something like this work? https://github.com/pigcan/extra-watch-webpack-plugin
It appears to add files to Webpack's file tracking. Assuming it works, changes to those files should be passed into this plugin as well.