Do not allow duplicate contact info

[juntao]

When the user submits the play form, we should check against all players retrieved by that page. If the contact info is duplicate, we should not let the user submit.

[Atlasoin]

When loading all players, their emails are kept in a global contacts variable. Just for raising a bit difficulty in getting all players' emails, a hashCode function is implemented.

var email = rpi[3].split(":")[1].trim();
contacts.push(hashCode(email))

When submit, the input email will be checked. For better usability, regex checking email format is also added:

        if (contacts.indexOf(hashCode(contactId)) !== -1){
            tip.error(lgb.contact_error);
            return;
        }
        if (!validateEmail(contactId)){
            tip.error(lgb.email_error);
            return;            
        }