[PATCH] Exception might get lost when ExecutorService is used

[jttt]

When task is executed using ExecutorService, any exception is ignored unless Future.get is called. This may hide some problems in code.

Provided patch modifies PleaseWaitRunnable so that it throws RuntimeException in EDT when exception during task execution is encountered. This behaviour is optional in case somebody wants to handle exception by himself. The default is throw exception in EDT.

It is not the best solution because not every task has to inherit from PleaseAndWaitRunnable and also exception is shown as JOSM error even if it's actually plugin error.

[stoecker]

In r1493.