Batch publish (#1138) * Batch Publish available on right clicking content projects when they have an org set * Can multi-select addons in asset browser to change publish status of multiple assets * CRC calculations happen in thread (less editor hitching when publishing) * Add Label.OpenExternalLinks (default to true) * Add BaseItemWidget.ItemsSelected event * Add AssetList.OnAssetsHighlight event * Add Checkbox.TriState