Junjie Zhang

Compatiblity issue with matplotlib version >=3.1.0

6

There are multiple imports of `matplolib.cbook.iterable` ([1](https://github.com/kdavies4/ModelicaRes/blob/76236906b604ba0fc1ccffb6c0a9400b869965d5/modelicares/util.py#L129), [2](https://github.com/kdavies4/ModelicaRes/blob/76236906b604ba0fc1ccffb6c0a9400b869965d5/modelicares/linres.py#L33)), however, this object is deprecated with maplotlib from version v3.1.0 ([source](https://matplotlib.org/3.1.1/api/cbook_api.html#matplotlib.cbook.iterable)). This has already causing import errors. An eassiest fix would be...