Screen Lock: Second round of addressing review comments

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

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

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

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

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

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

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

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

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

briar-android/src/main/res/values-ast/strings.xml

briar-android/src/main/res/values-bg/strings.xml

briar-android/src/main/res/values-br/strings.xml

briar-android/src/main/res/values-ca/strings.xml

briar-android/src/main/res/values-cs/strings.xml

briar-android/src/main/res/values-de/strings.xml

briar-android/src/main/res/values-es/strings.xml

briar-android/src/main/res/values-eu/strings.xml

briar-android/src/main/res/values-fa/strings.xml

briar-android/src/main/res/values-fi/strings.xml

briar-android/src/main/res/values-fr/strings.xml