Add Android project

.gitignore

README.md

android/.idea/gradle.xml

android/.idea/misc.xml

android/.idea/modules.xml

android/.idea/runConfigurations.xml

android/app/.gitignore

android/app/build.gradle

android/app/proguard-rules.pro

...privategrity/messagingclient/ExampleInstrumentedTest.java

android/app/src/main/AndroidManifest.xml

...n/java/com/privategrity/messagingclient/MainActivity.java

.../app/src/main/res/drawable-v24/ic_launcher_foreground.xml

android/app/src/main/res/drawable/ic_launcher_background.xml

android/app/src/main/res/layout/activity_main.xml

android/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

.../app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

android/app/src/main/res/mipmap-hdpi/ic_launcher.png

android/app/src/main/res/mipmap-hdpi/ic_launcher_round.png

android/app/src/main/res/mipmap-mdpi/ic_launcher.png