Centering of part labels #2
Description
Current the glyph labels are positioned so that the start of the glyph and the label and vertically aligned. I think it would generally look better if the horizontal middle were aligned instead.
The difference is particularly clear for short labels on the CDS glyph (irregular pentagon), or the RBS glyph (semicircle).
Note that if the text-anchor attribute of a SVG text element is set to middle, then the x attribute directly sets the horizontal position of the middle of the text.