Sandbox SVG elements to avoid ID conflicts (#51)
Sandbox SVG elements to avoid ID conflicts (#51)

Arrows in the sequence diagrams use SVG-markers for the messqge arrows,
and since the extension has to have to the DOM both the light and the
dark diagrams and hide the less relevant one, it used to produce
conflicts which confuse the rendering engine into using the hidden light
arrows for the dark diagram.
Sandboxing the images within img tags resolves the issue.

Refs: https://github.com/jaime-olivares/yuml-diagram/issues/10
Fixes: https://github.com/jaime-olivares/vscode-yuml/issues/50
jaime-olivares/vscode-yuml