QtIFW

Extend and fix KDJob.

- Supersedes http://codereview.qt-project.org/#change,14386
- Extend the class with a timeout, once the timeout gets hit
  the execution will be canceled.
- Fix delete later, as a subclass can emit finished without the
  super class and than delete later wouldn't be called at all.
- We can't use a single shot timer here, as we would hit a possible
  timeout once we use the class as stack object. Always restart the
  timer. A value of -1 will stop the timeout timer.

Change-Id: Ib8aef07209557e1ad362759ce16930aebbd9bdf3
Reviewed-by: Tim Jenssen <tim.jenssen@nokia.com>