Doc: Polish Qt::ConnectionType descriptions

- Shorten Qt::AutoConnection description, rearrange to match the order
  of the subsequent rows.
- Note the thread used in Qt::DirectConnection
- "Emitter's thread" is ambiguous -- a signal is not necessarily
  emitted from the thread that the emitter lives in.
- Misusing Qt::BlockingQueuedConnection WILL (not "can") cause a
  deadlock. Qt even issues an error message before it freezes.
- Remove the \note command -- it breaks the table and displays the note
  in a new paragraph.

Change-Id: Ib60cb665e0cd23e1e072402ec5d8be344b8454f7
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Add mtdev configure test

Change-Id: If989b479ed4babf902099c54be59ae73512820d5
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>