improve error handling, fix for #232

[OnnoEbbens]

I added some error handling that waits a second before trying again if a 429 is encountered.

[OnnoEbbens]

Thanks for the suggestion Martin that is a better way to handle retries. Pretty hard to find some good documentation on this, in the end this website helped me to understand the retry logic: https://oxylabs.io/blog/python-requests-retry

[OnnoEbbens]

The KNMI notebook raises an error in the test and the documentation. Locally I have no issues. I will try to merge and see if this error persists