Explain benefit in readme

[andywer]

Hey there!

Just stumbled upon your plugin. It might be cool if you have a large project and by using this plugin the webpack dev server uses less memory or gets faster.

But right now this is just an assumption. Could you explain what benefit this plugin is trying to achieve? I am quite puzzled :)

Cheers!

[jmfrancois]

Most JS project must run on all plateform so we can't use watchman which only works on unix based system.

Use watchman means the system notify webpack that a file has changed which is far better :) and more efficient than a loop on all files to see if they have changed ...

this is the same as gulp-watch (do not use gulp.watch but gulp-watch which use watchman)