SET, SHOW FIELDS, LIKE, etc support

Hi.

I've added some fixes and now it is possible to connect to myproto from Rails.

Rails mysql adapater sends a lot of specific mysql stuff and libmysqlclient reacts badly if we respond wrong.

I've fixed all incompatibilities (as for Rails 3.2 with mysql2) and now it is possible to connect to server with mysql2 gem and request data into ORM.