[Qt] addressbookpage: make addressbookpage use message() / remove optionsmodel

Related to #3159 and #3160 (same changes for transactionview and walletview).

Goal: Harmonize user experience for export of addresses, transactions and backup of the wallet!

![export_addr](https://f.cloud.github.com/assets/1419649/1414006/c2433602-3e62-11e3-8743-bbb0f3ad0599.png)