Merge pull request #817 from pybamm-team/issue-759-non-smooth-dae

#759 add changelog

Author: martinjrobins

CHANGELOG.md

@@ -66,6 +66,7 @@
 
 ## Breaking changes
 
+-   Model events are now represented as a list of `pybamm.Event` ([#759](https://github.com/pybamm-team/PyBaMM/issues/759)
 -   Removed `ParameterValues.update_model`, whose functionality is now replaced by `InputParameter` ([#801](https://github.com/pybamm-team/PyBaMM/pull/801))
 -   Removed `Outer` and `Kron` nodes as no longer used ([#777](https://github.com/pybamm-team/PyBaMM/pull/777))
 -   Moved `results` to separate repositories ([#761](https://github.com/pybamm-team/PyBaMM/pull/761))