Add margin in vertical scalar bar between title and bar.

Add a setting to fine tune the distance between the bar and the title.

Change-Id: I64cc824c70126a3854c501cc65335d6421835a75
Update baseline image.

Change-Id: Ie571d417ffdac4c44ead2fbb42080ac03cfc60e5
Read requested Exodus block-attributes.

Previously, these were not read. This fixes the
`GetCacheOrRead` method to call the exodus routine with
the proper arguments and adds in a place to request them
from the cache when assembling cell-data arrays.

Note that float vs. double arrays are not currently handled properly.

Change-Id: Iac2063d5cfabed7b90aa48b74169e88036724b1c
BUG #14273: Don't segfault when mapper has empty input.

vtkPainterPolyDataMapper segfaults when input is empty. That's unnecessary. This
check avoids that segfault.

Change-Id: Ie572e3963c85d7c71abad644eebc4313ed93992d
Test that exodus attributes can be read properly.

Change-Id: Ib1c2cb5fbb740a6a061dd60986460aa4e7b8d863
Merge topic 'fix_segfault_on_invalid_input' into master

f694dbf2 BUG #14273: Don't segfault when mapper has empty input.
Merge topic 'exodus-attrib' into master

02452ebb Test that exodus attributes can be read properly.
577db105 Read requested Exodus block-attributes.
Merge topic 'scalar-bar-margin' into master

a2b1ba7b Update baseline image.
5a8c6139 Add margin in vertical scalar bar between title and bar.