Fixed FileManager::prop() on multi-file selects, simplified query for SQLite and PostgreSQL
Fixed FileManager::prop() on multi-file selects, simplified query for SQLite and PostgreSQL

AxorB/elefant,R-J/elefant,Open343/elefant,AxorB/elefant,Open343/elefant,evan70/elefant,jbroadway/elefant,AxorB/elefant,twheel/elefant,twheel/elefant,Open343/elefant,jbroadway/elefant,jbroadway/elefant,R-J/elefant,R-J/elefant,evan70/elefant,evan70/elefant,jbroadway/elefant,twheel/elefant