added safe public methods to store

[artem-webdev]

added safe public methods to store

for exapmle

func (h *waHandler) HandleNewContact(contact whatsapp.Contact) {

    err := h.wac.Store.AddContact(contact)
    if err != nil {
        log.Println(err)
        return 
    }

}
...etc

[artem-webdev]

it can be seen that the store does not use the connect, so let there be methods for store object

[artem-webdev]

@SchulteMK Still in progress? - no, this is final

[beshoo]

@SchulteMK please can you review this PL. With Regard