New features and bug fixes

- Modifications made to the request package. Planned improvements will be
sending requests on intervals, rate limiter back off support, dynamic tuning
and requests packaged into a request job group.
- Can modify each exchanges individual HTTP client (e.g timeout and
transport settings).
- Bot now uses an exchange config HTTP timeout value.
- Bot now uses a global HTTP timeout (configurable).
- Batched ticker request support for exchanges.
- Ticker and Orderbook fetching now are spanned accross multiple
go routines and regulated by a sync wait group.
- Fixes hack used to load exchanges, now uses a sync wait group.
- Ticker and Orderbook storage and fetching now uses mutex locks.
- New pair function for finding different pairs between two supplied
 pair arrays. This is used for currency pair updates for exchange which
support dynamic updating.
- Shows removal/additions of dynamic updates currencies.

exchanges/ticker/ticker.go

@@ -3,6 +3,7 @@ package ticker
 import (
 	"errors"
 	"strconv"
+	"sync"
 
 	"github.com/thrasher-/gocryptotrader/common"
 	"github.com/thrasher-/gocryptotrader/currency/pair"
@@ -20,6 +21,7 @@ const (
 // Vars for the ticker package
 var (
 	Tickers []Ticker
+	m       sync.Mutex
 )
 
 // Price struct stores the currency pair and pricing information
@@ -85,6 +87,8 @@ func GetTicker(exchange string, p pair.CurrencyPair, tickerType string) (Price,
 
 // GetTickerByExchange returns an exchange Ticker
 func GetTickerByExchange(exchange string) (*Ticker, error) {
+	m.Lock()
+	defer m.Unlock()
 	for _, y := range Tickers {
 		if y.ExchangeName == exchange {
 			return &y, nil
@@ -96,6 +100,8 @@ func GetTickerByExchange(exchange string) (*Ticker, error) {
 // FirstCurrencyExists checks to see if the first currency of the Price map
 // exists
 func FirstCurrencyExists(exchange string, currency pair.CurrencyItem) bool {
+	m.Lock()
+	defer m.Unlock()
 	for _, y := range Tickers {
 		if y.ExchangeName == exchange {
 			if _, ok := y.Price[currency]; ok {
@@ -109,6 +115,8 @@ func FirstCurrencyExists(exchange string, currency pair.CurrencyItem) bool {
 // SecondCurrencyExists checks to see if the second currency of the Price map
 // exists
 func SecondCurrencyExists(exchange string, p pair.CurrencyPair) bool {
+	m.Lock()
+	defer m.Unlock()
 	for _, y := range Tickers {
 		if y.ExchangeName == exchange {
 			if _, ok := y.Price[p.GetFirstCurrency()]; ok {
@@ -123,6 +131,8 @@ func SecondCurrencyExists(exchange string, p pair.CurrencyPair) bool {
 
 // CreateNewTicker creates a new Ticker
 func CreateNewTicker(exchangeName string, p pair.CurrencyPair, tickerNew Price, tickerType string) Ticker {
+	m.Lock()
+	defer m.Unlock()
 	ticker := Ticker{}
 	ticker.ExchangeName = exchangeName
 	ticker.Price = make(map[pair.CurrencyItem]map[pair.CurrencyItem]map[string]Price)
@@ -152,18 +162,22 @@ func ProcessTicker(exchangeName string, p pair.CurrencyPair, tickerNew Price, ti
 
 	if FirstCurrencyExists(exchangeName, p.FirstCurrency) {
 		if !SecondCurrencyExists(exchangeName, p) {
+			m.Lock()
 			a := ticker.Price[p.FirstCurrency]
 			b := make(map[string]Price)
 			b[tickerType] = tickerNew
 			a[p.SecondCurrency] = b
 			ticker.Price[p.FirstCurrency] = a
+			m.Unlock()
 			return
 		}
 	}
 
+	m.Lock()
 	a := make(map[pair.CurrencyItem]map[string]Price)
 	b := make(map[string]Price)
 	b[tickerType] = tickerNew
 	a[p.SecondCurrency] = b
 	ticker.Price[p.FirstCurrency] = a
+	m.Unlock()
 }