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/r8-rules.pro

@@ -0,0 +1,17 @@
+# R8 for the Android 4.1 build (build.sh): shrinks ExoPlayer and Guava to what the app uses and turns their Java 8
+# code into what Android 4.1 runs. The app (and its Bouncy Castle copy) stays whole and readable in crash reports.
+-keep class com.minamp.** { *; }
+-dontobfuscate
+# referenced only by annotations, or by code for newer Androids that ExoPlayer guards by version
+# (build.sh gives R8 the Android 4.1 API, so anything newer is "missing")
+-dontwarn android.**
+-dontwarn androidx.annotation.**
+-dontwarn org.checkerframework.**
+-dontwarn com.google.errorprone.annotations.**
+-dontwarn com.google.j2objc.annotations.**
+-dontwarn javax.annotation.**
+-dontwarn kotlin.**
+-dontwarn org.codehaus.mojo.animal_sniffer.**
+-dontwarn sun.misc.Unsafe
+-dontwarn java.lang.ClassValue
+-dontwarn javax.lang.model.element.Modifier