add focus project, fix recovery save on ui thread, fix grid commit, wave_sdk submodule, use PlatformActivity as base for android/quest/focus and extend VRActivity on focus.

android/android/build.gradle

@@ -64,13 +64,13 @@ def ver_tag = "git describe --tags --abbrev=0".execute().text.trim()
 println classpath
 
 android {
-    compileSdkVersion 26
+    compileSdkVersion 28
     android.buildToolsVersion "28.0.3"
 
     defaultConfig {
         applicationId = 'com.omixlab.panopainter'
         minSdkVersion   19
-        targetSdkVersion 26
+        targetSdkVersion 28
         versionCode ver_count
         versionName "${ver_tag}.${ver_count}"
         // This block is different from the one you use to link Gradle

android/android/src/main/java/com/omixlab/panopainter/PlatformActivity.java

@@ -0,0 +1,6 @@
+package com.omixlab.panopainter;
+
+import android.app.NativeActivity;
+
+public class PlatformActivity extends NativeActivity {
+}