xiami connector: Get unique ID
xiami connector: Get unique ID

Also update selectors. For the `playButtonSelector`, using class selector
instead so that no need to redefine the `isPlaying` function.

alexesprit/web-scrobbler,Paszt/web-scrobbler,alexesprit/web-scrobbler,inverse/web-scrobbler,galeksandrp/web-scrobbler,fakelbst/Chrome-Last.fm-Scrobbler,inverse/web-scrobbler,Paszt/web-scrobbler,david-sabata/web-scrobbler,david-sabata/web-scrobbler,carpet-berlin/web-scrobbler,galeksandrp/web-scrobbler,carpet-berlin/web-scrobbler,fakelbst/Chrome-Last.fm-Scrobbler