Make jpype.JException catch exceptions from subclasses

Without this patch
```
try:
  javaobj.methodThrowsSubclassOfParentException()
except jpype.JException(ParentException), e:
  # Only catches ParentException but no subclasses of ParentException
  pass
```

With my patch
```
try:
  javaobj.methodThrowsSubclassOfParentException()
except jpype.JException(ParentException), e:
  # Catches ParentException and all subclasses of ParentException
  pass
```