Delete all app data when deleting account. #263

briar-android/src/org/briarproject/android/BaseActivity.java

...droid/src/org/briarproject/android/NavDrawerActivity.java

...ndroid/src/org/briarproject/android/PasswordActivity.java

...id/src/org/briarproject/android/SplashScreenActivity.java

...rg/briarproject/android/panic/PanicResponderActivity.java

...droid/src/org/briarproject/android/util/AndroidUtils.java

briar-core/src/org/briarproject/util/FileUtils.java