1.8.1 - Seek fix, Shorts in Subscriptions, sign-in fixes

Improvements

• Shorts in Subscriptions got their own shelf, with an "All" button that pulls every short your channels have posted, straight from the channel feeds. Two new switches in Settings → Shorts: which player they open in, and whether they group into the shelf or stay inline as ordinary videos (#34)
• Channel filter in Subscriptions now includes that channel's Shorts, not just its long-form videos (#34)
• The sign-in screen has a "Copy code" button. The code was already hitting your clipboard when you tapped "Open google.com/device", but nothing told you that, and it was useless if you were typing the code on a laptop (#35)
• The sign-in screen is translated — it had been hardcoded English since the first version. It also passes your language to the Google page it opens, which otherwise picks one by IP (#35)

Fixes

• Sign-in survives an expired code. Codes time out while you're typing them, and the screen would sit there with an untranslated error and no way forward except relaunching the app. It pulls a fresh code on its own now, with a "Try again" button as a fallback (#35)
• Videos no longer jump back to the start. When the app re-resolved a stream (expired URL, mid-playback error), it read the position off the freshly created player, which is always zero. Most noticeable in the first minutes of a video, where recoveries are frequent
• Cards in Shelf Rails size to the screen. They were fixed at 280 points, so on an iPad the next card sat almost entirely off the edge
• The app icon updates after the rename. iOS was still serving the cached YTLite one