resolve files inside subfolder as if in root

[Almir Kadric]

Currently quite a lot of library projects will contains a src folder and a build folder. The build folder would be used to just serve and require from html script tag, however the src folder would be used for optimized builds by only taking what you need with webpack or something similar.

This introduces require('<module>/src/<file>') all over the place. Though in webpack this can be worked around with some additional configuration, it would be nice if this spec covered this scenario and allowed the user to redirect all files to a subfolder.

"browser": "./src" or something similar