Fixes a crash on login and another when clicking the mention button on an account page that hasn't loaded yet.

app/src/main/java/com/keylesspalace/tusky/AccountActivity.java

@@ -481,6 +481,10 @@ public class AccountActivity extends BaseActivity {
                 return true;
             }
             case R.id.action_mention: {
+                if (loadedAccount == null) {
+                    // If the account isn't loaded yet, eat the input.
+                    return false;
+                }
                 Intent intent = new Intent(this, ComposeActivity.class);
                 intent.putExtra("mentioned_usernames", new String[] { loadedAccount.username });
                 startActivity(intent);
@@ -488,6 +492,7 @@ public class AccountActivity extends BaseActivity {
             }
             case R.id.action_open_in_web: {
                 if (loadedAccount == null) {
+                    // If the account isn't loaded yet, eat the input.
                     return false;
                 }
                 Uri uri = Uri.parse(loadedAccount.url);

app/src/main/java/com/keylesspalace/tusky/LoginActivity.java

@@ -217,8 +217,8 @@ public class LoginActivity extends AppCompatActivity {
     }
 
     @Override
-    protected void onPause() {
-        super.onPause();
+    protected void onStop() {
+        super.onStop();
         SharedPreferences.Editor editor = preferences.edit();
         editor.putString("domain", domain);
         editor.putString("clientId", clientId);
@@ -238,8 +238,8 @@ public class LoginActivity extends AppCompatActivity {
     }
 
     @Override
-    protected void onResume() {
-        super.onResume();
+    protected void onStart() {
+        super.onStart();
         /* Check if we are resuming during authorization by seeing if the intent contains the
          * redirect that was given to the server. If so, its response is here! */
         Uri uri = getIntent().getData();