Exception handling should be improved, no exception should crash the optimizer

[abeham]

There should be almost no errors that crash the Optimizer as a whole. Maybe a solution along attaching an event handler to Application.ThreadException which a mainform window should provide to handle exceptions. I'm not too firm with exception handling in C# though. Found this to possibly be useful: ​http://stackoverflow.com/questions/337702/c-how-to-implement-one-catchem-all-exception-handler-with-resume

Finally there should be possibilities to issue warnings and errors (I think there should be a distinction) to the GUI.

We should also think about properly integrating a logging library and include a build configuration that makes use of this library. So that one can assemble a log-build of HL to give to someone who's having troubles which are perhaps difficult to find out otherwise.

[pfleck]

The ErrorDialog/ErrorHandling should explicitly handle AggregateExceptions by unwrapping/flattening the InnerExceptions. Currently, only a single InnerException (only the first one in case of an AggregateException) is displayed.