Android: Multiple improvements

- Save/resume state when closing/starting.
 - Error reporting - hopefully can figure out why it's not starting on
   some devices.
 - Reduce startup latency.
 - Add more options and descriptions to settings.

android/app/build.gradle

@@ -24,6 +24,10 @@ android {
             version "3.10.2"
         }
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
     defaultConfig {
         externalNativeBuild {
             cmake {