buildProduction should deduce root from input HTML-files

[msiebuhr]

Random idea for buildProduction:

Deduce the --root-parameter from the topmost common parent directory of the given input HTML-files.

(Don't know if that makes sense in larger setups, though.)

[Munter]

The basic idea is good, but I am not sure if it clashes with some previous design decisions. I guess @papandreou remembers more about the reasoning behind this.

As I see ti you might need to specify a document root like http-pub if you build a Js-bundle based on http-pub/js/myApplication/bundle.js because there might be relations as far out as the given root.

[papandreou]

We have at least one use case where the root !== the topmost dir with html files in it. Would you get rid of the switch completely or just change its default value?

[Munter]

I guess we could keep the switch, but make it optional and default to the path of the first argument.
How would we handle when there are multiple arguments though?
Only extrapolate the root from the path if there is one argument, and require a specific root if there are multiple arguments?