Fix tab title in Terminal.app

I've intended to affach a PR to the #362 but created a new one instead. My bad.

In Terminal.app only a window title is updated, but not a tab title.

The problem is that **7**, which was used solely for the Terminal.app, affects only a proxy icon and a window title.
**2**, which was suggested by @kienluu in #362, sets a window title. It also may set a tab title, but only if it's not set explicitly. **1** sets a tab title.

I think the correct combo for the Terminal.app is **7** and **1**.