Fix endColor[] indexing
Fix endColor[] indexing

It was indexing past its range by accident. I was able to see it via
a warning. However, it was hard to see because there are now too many
warnings being printed out.

Fix it. We might want to consider fixing other warnings too in the
near future.

Signed-off-by: Patrick Avery <743342299f279e7a8c3ff5eb40671fce3e95f13a@kitware.com>

OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz