Create scanners.ipynb

[losDaniel]

Created another notebook to explain how to create and use scanners. This felt necessary because of the complications with submitting TagValues and options to use the advanced filters.

[erdewit]

Thanks for the notebook! It took a while before I could try it out. Note that for reqScannerData there's no need for sleep or cancel, this is all handled automatically (unlike reqScannerSubscription). I'll change that in the notebook.

I noticed that the 'old' filters are no longer documented in the IB docs, only the new filtering via TagValues.