Upcoming features

- [x] add timing info
- [x] add message when pausing for delay
- [x] post data (raw with mime_type)
- [ ] test unusual keys, e.g. headers with `-` or other symbols
- [ ] test `<<*:` embedding
- [x] issue warning in case of unknown keys in yml
- [ ] allow case-insensitive matching (in particular headers)
- [ ] add conditional syntax
- [ ] allow for defaults in var substitution (`${DELAY:0}`)
- [ ] add “Faker”
- [ ] add `.isNotNull` matcher
- [ ] allow posting json array
- [x] review array syntax `json.0.id` vs `json[0].id`
- [x] use ValueCodable dependency
- [x] log response to file
- [x] log text/raw