Use `strip-json-comments` to allow comments in JSON config files.

Large JSON-formatted config files can get very unwieldy without comments, and feature parity with INI-formatted comments is a nice bonus. JSHint, king of gargantuan JSON config, switched to using this module [recently](https://github.com/jshint/jshint/pull/1580).

Incidentally, this also verifies the "local" .APPNAMErc pattern.