change of scheme for rubyReserve.

[btsimonh]

Create a real ruby with real characters, but ensure it has no width and is not visible. Add it before other content on the line. For 'both' add two, one for above, and one for below. This works for Chrome and Firefox. Note: the browser detection has been disabled but not removed. -webkit should no longer be required, and firefox and chrome seem to have similar behaviour now.

I spent a lot of time examining position of text with and without rubies. The addition of 'fake' rubies may not be the best way to go - using margin/padding may be better? I think the browser implementations are still young...

[btsimonh]

please compare existing tests in Chrome and Firefox. You can compare here: https://imsc-rosetta.github.io/imsc-rosetta-qualify/ with 'legacy' and 'patched' renderer. I'm not saying it's perfect, but it does need to work.

[btsimonh]

also addresses https://github.com/sandflow/imscJS/issues/236