Add support for recv_window parameter and custom options for REST client (#7)

* remove unused/unexisting method. Add missing semi-colon. Add support for recvWindow parameter, optional, with default value. Add support for custom sync time interval.

* add new params to rest client constructor

* add recv and sync as options object, optional, with updated docs

* cleaning

* whitespace

* allow override via params

* param consistency

Co-authored-by: tiagosiebler <ts@github.com>

doc/rest-client.md

@@ -4,9 +4,13 @@
 ## Class: RestClient
 
 
-### new RestClient([key][, secret])
+### new RestClient([key][, secret][, livenet][, options])
 - `key` {String} Bybit API Key
 - `secret` {String} Bybit private key
+- `livenet` {Boolean} If false (default), use testnet.
+- `options` {Object} Optional settings for custom behaviour.
+  - `recv_window` {Number} Optional, default 5000. Increase if recv errors are seen.
+  - `sync_interval_ms` {Number} Optional, default 3600000. Interval at which syncTime is performed.
 
 If you only use the [public endpoints](#public-endpoints) you can ommit key and secret.