[NEW] Added request timeout option. Set via env var COUCH_REQUEST_TIMEOUT,
as CLI option --request-timeout, or programmatically via
options.requestTimeout.
[IMPROVED] Replaced usages of Node.js legacy URL API. Note this changes some
URL validation error messages.
[IMPROVED] Documentation, help text and log warnings for invalid options in
"shallow" mode.
[UPGRADED] Moved nodejs-cloudant dependency to 4.x.x.