I thought that the pressHold that gives the bookinfo was super undiscoverable because the pressInterval is so long.
So, I've added an indicator on the book tile that animates as the pressHold progresses.
Two downsides to this patch:
- I cannot figure out how to get the actual press interval from Qt Style Hint
- Only Bookshelf has the fileinfo thing, searchbox and welcome page don't. We should fiugre out whether to disable it for those or to implement the bookinfo overlay.