[Azoth Xoox] Xep0313ModelManager::Jid2Index() for #1536.
[Azoth Xoox] History messages requesting for #1536.
[Azoth] Check only history indices rows.
[Azoth Xoox] Try messages with XEP-0313 manager for #1536.
[Azoth Xoox] Implement IHaveServerHistory.

This finally closes #1536.