Meshfill plot with Mercator projection issue

[sankhesh]

This use case currently fails. Test case provided in 9d6bed6

Run ctest -V -R vcs_test_animate_projected_meshfill_mercator

Error Reported:

File "<uvcdat>/install/lib/python2.7/site-packages/cdms2/coord.py", line 289, in subSlice
newbounds = bounds[specs]   # bounds can be a numarray or DatasetVariable
IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

[doutriaux1]

@sankhesh I fixed @aashish24 code so that it now passes (branch: issue_1671_meshfill_mercoator). But there is a more fundamental issue here, cdms2 does not "shrink" curvilinear grids when subsetting but rather masks out cells that are not within that range, so @aashish24 code does not help in this case.

It maybe better to copy the graphic method and set the limits ourselves, if you do so it works
in the test I add simply do:

m.datawc_y1=-85
m.datawc_y2=85

Then it works and plots:

[doutriaux1]

@aashish24 @chaosphere2112 @williams13 not sure how to proceed from here, suggestions welcome.