Since this is meant to run as a service, sites should be able to flag themselves as disabled.

Like event runners, leave event retreiver workers active, looping only to retreive list of sites to check

Sites list is dynamic, need to retreive sites' events is not.

Init script needs customization to fully support multiple networks, but if the network ID is nonstandard, this will do.

See 758c08ab

CSV is too hacky, and it was only used because #113 disguised why JSON didn't work.

Partially revert 59f81411, obviated by 536d0079

Ensure WP-CLI's `--quiet` flag is respected

From `line()`'s inline doc:

> Display informational message without prefix, and ignore `--quiet`.