Request package update & rate limit system expansion (#413)

* Initial rework of rework of requester - WIP

* Implementing and checking rate limits - WIP

* implemented coinbene rate limiting shenanigans

* add in remaining WIP

* fixy

* use authenticated rate limit

* drop ceiling as this can be done with a counter later

* add functionality to struct

* purge config options for rate limiting so as to keep things minimal

* prepare futures and swap rate limiting for implementation

* Address linter issues

* Addressed nits, fixed race

* fix linter issue

* remove global var as this was only setting when newrequester was called

* moved rate limit functionality into its own file

* Update Bitfinex with correct rate limit and test endpoints (WIP)

* finish off bitfinex adjustments

* fixes

* fix linter issues

* slowed rate for coinbasepro

* drop rate limit for huobi as the doc times have intermittent 429 issues.

* Set MACOSX_DEPLOYMENT_TARGET to remove linking warning

* Addr Thrasher nits

* Addr glorious nits

* unexport do request function

* fixed nitorinos

* Fixed something I missed

* move disabled rate limiter into loadexchange and use interface functionality

* Add temp quick fix

exchanges/bittrex/bittrex_wrapper.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"strings"
 	"sync"
-	"time"
 
 	"github.com/thrasher-corp/gocryptotrader/common"
 	"github.com/thrasher-corp/gocryptotrader/config"
@@ -99,9 +98,8 @@ func (b *Bittrex) SetDefaults() {
 	}
 
 	b.Requester = request.New(b.Name,
-		request.NewRateLimit(time.Second, bittrexAuthRate),
-		request.NewRateLimit(time.Second, bittrexUnauthRate),
-		common.NewHTTPClientWithTimeout(exchange.DefaultHTTPTimeout))
+		common.NewHTTPClientWithTimeout(exchange.DefaultHTTPTimeout),
+		request.NewBasicRateLimit(bittrexRateInterval, bittrexRequestRate))
 
 	b.API.Endpoints.URLDefault = bittrexAPIURL
 	b.API.Endpoints.URL = b.API.Endpoints.URLDefault