Using nested event loops to achieve synchronous call behavior while doing Akonadi jobs has created way to many issues due to unexpected re-entrancy.

This is basically backport of a series of changes in trunk which replace this form of blocking with real blocking of the caller and delegating the Akonadi job execution to a worker thread.

This should fix all the bugs this is sent to. If they remain with 4.2.1 once it is released, please re-open.

Darío, in case I missed some of the eventloop related bugs, please feel free to close them as well.