Fix a lot of bugs :

*  Missing center in PreferencesPanel for categories suppression
*  Previous not checked operations needs to be inverted (positive if negative, and negative if positive)
*  New operation needs to be sorted before insertion in InsertIntoGrid (GridAccount.cpp)

src/view/PreferencesPanel.cpp

@@ -273,6 +273,8 @@ void PreferencesPanel::InitCategories(User* user)
             wxFont font = user->GetCategoryFont(it->id);
             SET_ROW_FONT(curLine, font);
         }
+
+        _categoriesGrid->SetCellAlignment(curLine, CATEGORY_DELETE, wxALIGN_CENTRE, wxALIGN_CENTRE);
     }
 
     _categoriesGrid->SetReadOnly(0, CATEGORY_NAME, true);