Hello doggenj.
First sorry for my bad english. I took a look for your library. I think it's a good idea to do a library for a lot filters. I see you did it only 5 days ago. I hope you continue the development of this library. I think it's very important you do an explanation of your library. Characteristics of Bessel and Chebyshev filters, what is filter order.I don't see any explanation for your library for the functions and parameters ("b" is Bessel filter, "c" is...). Either any explanation in the examples.
For last, in your library I don't see the parameter for the frequency corner. I see it's very important, isn't? And value and filtered are declared as int. Could it be poor for any applications? Could it be better to declare as long or float?
I talk you for you can improve your library because I think it's a great idea.