- Changed `width` and `height` values to be based om `getBoundingClie…

…ntRect` rather than `offsetWidth` and `offsetHeight` ([which are integers](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/offsetWidth#value) and can cause rounding/flickering problems in some cases).

Merge pull request #82 from hoxyq/use-ResizeObserver-global-from-pare…

…ntNode-realm

fix: use ResizeObserver global from parentNode realm to support case with multiple realms