Change Signature -> Propagate Exceptions -> Toolbar added with Expand Al...

Dear IntelliJ Team,

this pull request adds an Expand All / Collapse All toolbar button. 

If you want to propagate an exception to all methods in a deep call hierarchy it can be automatically expanded which saves a lot of time.

The only problem is, that it can take a lot of time if the hierarchy is very big and I don't know yet how to display a progress bar which let's the user cancel the operation.

It would be nice if you could add this functionality to IntelliJ. Thanks.

Best regards

Josef