Started with `localstack start` then navigated to `http://localhost:4569/shell`

Localstack version is `0.10.5`

![Screenshot from 2019-11-26 08-15-03](https://user-images.githubusercontent.com/57932946/69588919-24798700-1025-11ea-94d2-9cfb6dd20004.png)

Console log below, its all the same so I am just posting one

```2019-11-26T00:13:18:ERROR:localstack.services.generic_proxy: Error forwarding request: the JSON object must be str, bytes or bytearray, not NoneType Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/generic_proxy.py", line 240, in forward
    path=path, data=data, headers=forward_headers)
  File "/opt/code/localstack/localstack/services/dynamodb/dynamodb_listener.py", line 44, in forward_request
    data = json.loads(to_str(data))
  File "/usr/lib/python3.7/json/__init__.py", line 341, in loads
    raise TypeError(f'the JSON object must be str, bytes or bytearray, '
TypeError: the JSON object must be str, bytes or bytearray, not NoneType```

try:
                ProxyListenerDynamoDB.thread_local.existing_item = find_existing_item(data)
            except Exception as e:
                if 'ResourceNotFoundException' in str(e):
                    return get_table_not_found_error()
                raise
        elif action == '%s.DescribeTable' % ACTION_PREFIX:
            
            table_names = ddb_client.list_tables()['TableNames']
            if to_str(data['TableName']) not in table_names:
                return get_table_not_found_error()
        elif action == '%s.DeleteTable' % ACTION_PREFIX:
            
            table_names = ddb_client.list_tables()['TableNames']
            if to_str(data['TableName']) not in table_names:
                return get_table_not_found_error()
        elif action == '%s.BatchWriteItem' % ACTION_PREFIX:
            existing_items = []
            for table_name in sorted(data['RequestItems'].keys()):
                for request in data['RequestItems'][table_name]:
                    for key in ['PutRequest', 'DeleteRequest']:
                        inner_request = request.get(key)
                        if inner_request:
                            existing_items.append(find_existing_item(inner_request, table_name))
            ProxyListenerDynamoDB.thread_local.existing_items = existing_items
        elif action == '%s.TransactWriteItems' % ACTION_PREFIX:
            existing_items = []
            for item in data['TransactItems']:
                for key in ['Put', 'Update', 'Delete']:
                    inner_item = item.get(key)