fix bug, redis session doesnt work

fixed bug: in logs package check if platform is windows

orm 1. add api: NewOrmWithDB, AddAliasWthDB; 2. RawSeter -> add api: RowsToMap, RowsToStruct; 3. RawSeter -> change api: Values, ValuesList, ValuesFlat add optional params comumns.

* regenerate sid, if the old key doesn't exists, set the new one directly

Add a ReadOrCreate method:

m := &User{Name: "Kyle"}
// Returns a boolean indicating whether the object was created,
// the primary key of the object, or an error.
created, id, err := orm.ReadOrCreate(m, "Name")

diffrent level logs display diffrent color

add comments for orm and middleware packages.

Update README.md

Example:
peers = one;Two;Three

Update SessionExist to close the db connection

close the mysql connection

use connection pool for redis, support auto connection

fix #453

support redis cache auto connection