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

it is named qEncode

log file name bug fixed

this bug happens when daily rotate. ex,when it is 2016-01-22 23:59:59 and need a rotate,the file name should named with 2016-01-22 but named with 2016-01-23(next day)

Fixed #1586

fix path issue #1613

fix issue #1566