Having a HoverHandler covering the root ApplicationWindow causes
problems for some Qt Quick Controls with pen/touch, e.g. it's impossible
to focus a TextArea/TextField.
The HoverHandler is moved to HToolTip (since it's used for those),
targets the ApplicationWindow but is now only enabled while a tooltip is
visible.
If the requested object in states.json exists but doesn't contain the
property we're looking for, return the default value (passed to the
function) instead of undefined.
Use native ListModel which require a lot of changes, but should be
much faster than the old way which exponentially slowed down to a crawl.
Also fix some popup bugs (leave/forget).
Not working yet: side pane keyboard controls, proper highlight,
room & member filtering, local echo replacement
