Overlapping Elements in IEA 15 MW Mesh

[JustinPorter88]

Sometimes overlapping elements get created.

This appears closely related to the fundamental problem in Issue #20. However, that was not fixed by merging nodes to make meshes repeatable.

Example plot of the mesh issues can be generated by setting this to True and running the test:

SONATA/tests/regression/1_iea15mw/test_iea15mw.py

Line 92 in 09e6963

compare_mesh = False