Merge branch '1247-pin-lock' into 'master'

briar-android/build.gradle

briar-android/src/main/AndroidManifest.xml

...java/org/briarproject/briar/android/AndroidComponent.java

...project/briar/android/AndroidNotificationManagerImpl.java

...c/main/java/org/briarproject/briar/android/AppModule.java

...ain/java/org/briarproject/briar/android/BriarService.java

...java/org/briarproject/briar/android/TestingConstants.java

...g/briarproject/briar/android/account/LockManagerImpl.java

...riarproject/briar/android/activity/ActivityComponent.java

...rg/briarproject/briar/android/activity/BriarActivity.java

...org/briarproject/briar/android/activity/RequestCodes.java

...rg/briarproject/briar/android/login/PasswordActivity.java

.../org/briarproject/briar/android/login/UnlockActivity.java

...iarproject/briar/android/navdrawer/NavDrawerActivity.java

...briarproject/briar/android/settings/SettingsFragment.java

...iarproject/briar/android/splash/SplashScreenActivity.java

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

...project/briar/api/android/AndroidNotificationManager.java

.../java/org/briarproject/briar/api/android/LockManager.java

briar-android/src/main/res/layout/activity_unlock.xml