Hoard 2.8.3

Faster with large libraries, in both pages and behind them. (There's no 2.8.2: a release by that name was
published by mistake without its files.)

• Only the cards near the screen are drawn. Both pages drew every card on each filter click or search
  keystroke; now they draw the first 120 and add more as you scroll.
• Tags that match a word are found through a word index, instead of trying every such tag on every name:
  20,000 names with 300 matching tags take about 0.1 s instead of 28 s, every time the library loads.
• The Downloads index is rebuilt without holding anything up. A sync no longer pauses after each download while
  the Downloads page asks for the index, and the Library page never waits for it.
• The library and downloads lists are gzipped when they're large: 28 times smaller, which helps when Hoard is
  opened from another device.