Hypercontagion

* Added compatibility for XGI 0.5.3 [2](https://github.com/nwlandry/hypercontagion/pull/2) (nwlandry).
* Sped up epidemic functions [2](https://github.com/nwlandry/hypercontagion/pull/2) (nwlandry).
* Removed random state decorators (nwlandry).

* Removed unnecessary files ([1](https://github.com/nwlandry/hypercontagion/pull/1)).
* Added a function to visualize contagion processes ([1](https://github.com/nwlandry/hypercontagion/pull/1)).
* Formatted notebooks with black and updated the requirements file to match ([1](https://github.com/nwlandry/hypercontagion/pull/1)).

Contributors: nwlandry