Improve PasswordActivity by

* removing screen border visible on small screens
* showing noticeable error message on wrong password input
* showing keyboard again after entering wrong password
* making lost password link easier to recognize as link
* renaming keyboard toggle method from 'hide' to 'toggle'

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

@@ -129,7 +129,7 @@ public class SetupActivity extends BaseActivity implements OnClickListener,
 	}
 
 	public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
-		hideSoftKeyboard();
+		toggleSoftKeyboard();
 		return true;
 	}