Shared chunks

[xwisdom]

Hello,

It would be nice if the following RollupJS features were included with the SytemJS Builder:

• Shared chunks are generated automatically to avoid code duplication between chunks/bundles.
• Filenames of generated chunks in the output folder correspond to the entry point filenames.

[ffflabs]

Uh... Do you have an example of such Roll-up behavior? I've only achieved such output using rollup-plugin-multi-entry which is a bit unpredictable.