Back button should save tag changes instead of canceling

astrid/plugin-src/com/todoroo/astrid/actfm/TagSettingsActivity.java

@@ -510,6 +510,15 @@ public class TagSettingsActivity extends FragmentActivity {
         return super.onCreateOptionsMenu(menu);
     }
 
+    @Override
+    public void onBackPressed() {
+        if (tagName.getText().length() == 0) {
+            finish();
+        } else {
+            saveSettings();
+        }
+    }
+
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         switch(item.getItemId()) {