Sync STS Viewer with version 1.2

[wendellpiez]

NISO STS is now at version 1.2.

The delta should be examined and any adjustments made, so that STS 1.2 documents function well in the viewer.

This work item does not require new features to be implemented, but identifying them would be good. The current viewer, of course, is made to be forward-compatible across v1.x.

[wendellpiez]

Notes:

• https://niso-sts.org/downloadables/NISO-STS-1-2-compare-1-0.pdf shows changes 1.0-1.2
• https://niso-sts.org/downloadables/samples/NISO-STS-Standard-1-0.XML linked from https://niso-sts.org/Samples.html gives formal names for 1.0 elements and attributes - this would be good to have for v1.2 also