Support detecting new entries

[zoubin]

Another way to fix #56

Unlike #146 , this implementation does not call the constructor function each time entries added or removed, but try to only manipulate the pipeline.

The command line:

cd example/files
../../bin/cmd.js main.js -o bundle.js --entry-glob='main*.js'

cp main.js main2.js
# edit `main2.js` and save to see the change

rm main2.js

API:

b.plugin('watchify', { entryGlob: '*.js' })

[zoubin]

Here is an example to show the case where multiple bundles are created.

[Zorgatone]

+1: I had problems watching multiple bundles. It would be great if the provided example would work like that

[rafegoldberg]

is there any update on this? it would, in my estimation, be a killer addition to Browserify's featureset!