discrepancies between ba_plot and plot_int

Ctest runs examples and stores output under build/test_output/PyPersist/. These output files (.int.gz) can be visualized using devtools/view/plot_int.py. The resulting images, however, differ from what we obtain by directly running the example scripts (with plots under control of Wrap/Python/ba_plot.py).

• The color scales deviate. We should force plot_int to use the color scale of ba_plot.
• Units and axis ticks differ. Under plot_int, the conversion factor 180/pi seems to applied twice
• The .int.gz files contain axis ranges but do not indicate units Won't fix; using internal units.