Redo http Transport code

* Insert User-Agent in Transport - fixes #199
  * Update timeouts to use Context
  * Modernise transport

fs/http_old.go

@@ -0,0 +1,31 @@
+// HTTP parts pre go1.7
+
+//+build !go1.7
+
+package fs
+
+import (
+	"net"
+	"net/http"
+	"time"
+)
+
+// dial with timeouts
+func dialTimeout(network, address string, connectTimeout, timeout time.Duration) (net.Conn, error) {
+	dialer := net.Dialer{
+		Timeout:   connectTimeout,
+		KeepAlive: 30 * time.Second,
+	}
+	c, err := dialer.Dial(network, address)
+	if err != nil {
+		return c, err
+	}
+	return newTimeoutConn(c, timeout), nil
+}
+
+// Initialise the http.Transport for pre go1.7
+func (ci *ConfigInfo) initTransport(t *http.Transport) {
+	t.Dial = func(network, address string) (net.Conn, error) {
+		return dialTimeout(network, address, ci.ConnectTimeout, ci.Timeout)
+	}
+}