Return nil if config value does not exist or is empty

Need return empty []string  if config value is empty.

split `“”` ==> []string{}, Not []string{“”}

fix bug: session id undecoded when destroy and sesssion memory provider push wrong

fix #1595

colorful console and go fmt

try to fix the little bug when calling Close or Flush in async mode

lock the templates map when goroutie update the map

Added slack

Add GroupBy to QuerySeter

fix issue #1641

Add noColor option for console logger

Still same default behavior (with color)

 - Also added simple test

Fix Context.Input.SetParam not overwriting existing value

Config logic

 - Also added tests for Context.Input.Param handling