Request for file-by-file preview/pdf build option for multi-document content

[ayhy]

When editing publications with many files, often edits to single file do not result in change of total pages of the section, thus building whole book each time is not necessary.
However, just using vivliostyle build <filename> will not result in right page number or other css counters.
Similar issue is already mentioned in vivliostyle/vivliostyle-pub#153, and this function is useful in cli as well.
In cli, option such as --limit-render <filename in config.js or webpub file> would be great.