Plexamp Lite 1.14: Android 4.1 build with ExoPlayer, lyrics, home-screen widget

- One build per Android level, as in Tenda: build/PlexampLite.apk (Android 2.2+, versionCode 1508) and
  build/PlexampLite-api16.apk (Android 4.1+, 1516), from shared src/ plus platform/api8 or platform/api16.
- Android 4.1 build: ExoPlayer 2.18.7 behind a small Engine interface (gapless hand-over to read-ahead and
  downloaded files, a longer buffer, MediaPlayer fallback for tracks it can't decode), a notification and
  lock screen with art and buttons, a resizable widget, Holo, a menu button without a Menu key, metered networks.
  R8 shrinks ExoPlayer and Guava (tools/fetch_exoplayer.sh, tools/r8-rules.pro).
- Both builds: lyrics in Now Playing as in the Mac app (timed lyrics follow and seek), a home-screen widget,
  media play/pause keys, the moon icon drawn without clipPath.
- PlexampLite-noreport on the SD card stops play reports, for tests against a real server.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/fetch_exoplayer.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+# Fetches what the Android 4.1 build needs beyond tools/setup_toolchain.sh: ExoPlayer 2.18.7 (Google's Maven) and
+# Guava (Maven Central), checked against these SHA-256s, into $TOOLS/exoplayer-2.18.7 (TOOLS default ~/android-toolchain).
+# 2.18.7 because it's the newest that needs only Guava (2.19 adds AndroidX Core); every 2.x runs on Android 4.1.
+set -euo pipefail
+T=${TOOLS:-$HOME/android-toolchain}
+D=$T/exoplayer-2.18.7
+G=https://dl.google.com/dl/android/maven2/com/google/android/exoplayer
+M=https://repo1.maven.org/maven2/com/google/guava
+mkdir -p "$D"
+tmp=$(mktemp -d)
+trap 'rm -rf "$tmp"' EXIT
+get() {   # url sha256 file
+  if [ -f "$D/$3" ] && [ "$(shasum -a 256 "$D/$3" | cut -d' ' -f1)" = "$2" ]; then return; fi
+  curl -fsSL -o "$tmp/$3" "$1"
+  [ "$(shasum -a 256 "$tmp/$3" | cut -d' ' -f1)" = "$2" ] || { echo "$3: checksum mismatch"; exit 1; }
+  mv "$tmp/$3" "$D/$3"
+}
+for m in core:2b51c5f07aa25f89e4adb7a833073e1a4adc5b87a388bd0045ebc3429b1bf42f \
+         common:adfef7d3cbd69dd8fcc4ce05642a886c9fbc2764826bc39a6075ba6a0c62d003 \
+         datasource:cbe67ad9eaf94be7b35d1a625252a79ed5c18601d19f7b4d787acfbcea009208 \
+         decoder:598c0b444db71770f9b89b4e444e34cb03d5ed2eb5c12fb062afb2f9b05b9a1e \
+         extractor:c3e34c7b07ecd3c78a75bb7185671030bea4371ac88d854000a856fc05f7eeff \
+         database:31f0929246fb81296345be8414e7fa080a82deb8d382eb5d875974649030619d; do
+  a=${m%%:*}; sum=${m#*:}
+  get "$G/exoplayer-$a/2.18.7/exoplayer-$a-2.18.7.aar" "$sum" "exoplayer-$a.aar"
+  # an AAR is a zip: the code is classes.jar, the keep rules for apps that shrink it are proguard.txt
+  unzip -o -q -d "$tmp/$a" "$D/exoplayer-$a.aar"
+  cp "$tmp/$a/classes.jar" "$D/exoplayer-$a.jar"
+  if [ -f "$tmp/$a/proguard.txt" ]; then cp "$tmp/$a/proguard.txt" "$D/exoplayer-$a.pro"; fi
+  rm "$D/exoplayer-$a.aar"
+done
+get "$M/guava/31.0.1-android/guava-31.0.1-android.jar" 9425a423a4cb9d9db0356300722d9bd8e634cf539f29d97bb84f457cccd16eb8 guava.jar
+get "$M/failureaccess/1.0.1/failureaccess-1.0.1.jar" a171ee4c734dd2da837e4b16be9df4661afab72a41adaf31eb84dfdaf936ca26 failureaccess.jar
+ls "$D"