improve color feature for package glog

.example/os/glog/glog_color.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"github.com/gogf/gf/frame/g"
+)
+
+func main() {
+	g.Log().Print("Print")
+	g.Log().Debug("Debug")
+	g.Log().Info("Info")
+	g.Log().Notice("Notice")
+	g.Log().Warning("Warning")
+	g.Log().Error("Error")
+	g.Log().Critical("Critical")
+}