Update display stylesheets to accommodate multiple images within a single figure

[juliaflanders]

In cases where an author includes multiple image files for a single figure, it would be desirable to be able to encode these as a <table> within a <figure> (which is the output that TEIGarage generates from a Word document that includes multiple image files side by side). Currently, our display can accommodate this, but the stylesheet generates an extra "Table 1" caption because of the presence of the <table> encoding.

We need to update our XSLT so that when a table is embedded inside a figure, no "Table" heading/caption is generated.

Probably also prudent to discuss this change (John/Julia/Syd) to see whether it actually seems like a good idea.