Excluded private fields by default

[nojaf]

I think it makes sense to exclude private stuff by default.
Should be configurable via a flag. Also in the online tool.

• Command line tool
• Online tool

[nojaf]

Probably the vals to begin with.

[nojaf]

Private constructors are also a good candidate.

[nojaf]

Entire nested modules?

[nojaf]

Private members can never be skipped for structs.