dat init discards existing dat.json values

[gohai]

Bug Report

• Operating system: Linux (Fedora)
• Node Version: v10.16.3
• Dat Version: 13.13.1

Expected behavior

dat init should create a dat.json or, if it already exists, update selected properties (such as title and description) while keeping any previously set properties intact. (I am hoping to keep e.g. experimental intact for Beaker...)

Actual behavior

dat init discards all previously set properties in dat.json, creates a file that only has the title and description set.

Note

A similar issue was previously discussed in #148, but it seems the behavior has since changed (again?).

[okdistribute]

Hey, if you or someone you can recruit has time to open a PR fixing this, that would be welcome!