(refactoring) Remove redundant files.
Add Panel::GetChild():
1. Return ui::Widget* .
2. Fill a output after auto casting.
Improve WidgetBuilder::BulidImageView().
Fix: At PanelBuilder call m_panel->setName().
Add JsonUtils QueryInt().
Panel layout add support ui::Text.
Panel layout add support ui::TextBMFont.
Replace JsonUtils with JsonValue.