Please add field folding feature

[wangjiyang]

Hi Pawit,

This tool is great. I am using it when debugging some protobuf issues.
Sometimes the protobuf is really big, eg 16K bytes. It's impossible to check some fields because every field is packed in a html table. I proposed to add a feature that we can click a +/- button to fold a whole field. That would be great.

Thanks

[pawitp]

Thank you for your interest. I'm not actively adding any feature to this project right now but I'm more than happy to review and merge PRs adding the requested feature.