Add an integrator to the library

[drewr95]

I didn't see one when searching your library, if I missed it my apologies.

I have implemented my own that I think would do well here :). It is very similar to cyclic_value except it's clamped to the min and max range. It also has a compile-time MIN and MAX similar to cyclic value to save RAM.

Let me know if you'd like me to add it.