Test failures on Mac

[clevelam]

We (@salvesen-lanl and @clevelam) found a few issues with the test on Mac systems when working on #39. Three tests fail on Mac that seem fine on Linux. I think this is because the tests are ill posed (using 3D dumps on tests that expect 2D or 1D data). The data is duplicated at multiple x/y locations if we do not consider the y/z plain. There are a few simple work arounds all of which involve removing the duplicate data (in 1D/2D in the testing), either by changing the parser or adding 1D/2D specific dump files.