[Blasq] PhotosProxyModel::EmitDataChanged().
[Blasq] Provide info in the proxy about the multiple selection.
[Blasq] Notify the QML view about image selection mode.
[Blasq] PhotosTab::ImageID2Indexes().
[Blasq] Support multiple selection on C++ side.
[Blasq] Don't show standard buttons in selection mode.
[Blasq] Added toggle selection button to the QML.
[Blasq] Slightly better code.
[Blasq] Show highlight for multiple selected items.
[Blasq] Nice animated gradient change.