All test pass, except for the TestConfig suite, which is not too critical as the
plan for this version onwards is to avoid configuration as much as possible.
Documentation needs some improvement
The API has been simplified to only allow for ONE topology per
NetworkEnvironment.
This covers the main use case, and simplifies the code.
See CHANGELOG.md for a full list of changes
* Removed nxsim
* Refactored `agents.NetworkAgent` and `agents.BaseAgent`
* Refactored exporters
* Added stats to history