Fixes #385 -- an accessibility issue where screen readers cannot see table headers.
Proposed resolution
Use Bootstrap-style screen-reader only display for table headers
rather than display: none;
Append aria-hidden="true" to inserted cell labels, since they are
duplicative in the context of screen readers, which now can always see
table headers.
Problem/motivation
Fixes #385 -- an accessibility issue where screen readers cannot see table headers.
Proposed resolution
display: none;aria-hidden="true"to inserted cell labels, since they are duplicative in the context of screen readers, which now can always see table headers.