Incompatibilities with basemap and matplotlib versions

[xylar]

In my testing today, I found that MPAS-Analysis is not compatible with:

• basemap 1.2.0 because addcyclic is broken (see Fix adding map to list in addcyclic matplotlib/basemap#441)
• matplotlib 3.0.1 because of issues with ax._hold (see AttributeError: can't set attribute ax._hold = self._tmp_hold matplotlib/basemap#435)
• matplotlib 3.0.0 because of issue with tight layout (see colorbar fill whole figure matplotlib/basemap#426)

for now, basemap 1.1.0 and matplotlib 2.2.3 work well. When matplotlib 3.0.2 and basemap 1.2.1 are released, we should be able to use them (fingers crossed).

[xylar]

Addressed by #477