Catch runtime exception in data source and client generation and output error message to the user.
When data source ID is changed, delete state file instead of renaming it.
In Utils.getExceptionMessage, use the exception class name when no error message is available (to get "java.lang.NullPointerException" for NPE instead of "No message available")
Show the error message with the stack trace in the log window (when available)
…urce ID
Issue #126 v2.0.9