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

Fix regression caused by commit ad654793

Commit ad654793 will cause "Method Not Allow" in preflight response
when enable CORS plugin.

The root cause is that CORS plugin didn't generate http output after applied
commit ad654793, so the value of `ctx.ResponseWriter.Started` will be keep
`false`, and then later filter chains will be go on to run when CORS filter
finished.

This path will both fix "Method Not Allow" and the original bug
"multiple response.WriteHeader calls".
Signed-off-by: Yunkai Zhang <qiushu.zyk@taobao.com>

Fixed #1607

Fix utils mail some bugs