Fixed #4773: bug of UIButton's size when Scale9Enabled in test cases fixed
Revert "Issue #4741: Widget's addNode renamed to addChild"

This reverts commit dceecb9651d933649da61f5257a4065d6db47b33.
Issue #4741: Temporary fix for addNode function of ccui.Widget
Update README.md with prebuilt projects and alpha 2 informations