First prototype of Espresso test infrastructure with automatic screenshoting

bramble-android/build.gradle

briar-android/build.gradle

briar-android/fastlane/Screengrabfile

briar-android/proguard-test.txt

.../org/briarproject/briar/android/BriarTestApplication.java

...va/org/briarproject/briar/android/BriarTestComponent.java

...rg/briarproject/briar/android/settings/DarkThemeTest.java

.../org/briarproject/briar/android/test/BriarTestRunner.java

...a/org/briarproject/briar/android/test/ScreenshotTest.java

...java/org/briarproject/briar/android/test/ViewActions.java

.../org/briarproject/briar/android/BriarApplicationImpl.java

...ain/java/org/briarproject/briar/android/util/UiUtils.java

briar-android/src/screenshot/AndroidManifest.xml