Updating Travis' Qt version to 5.12 for QVariant::fromStdVariant.
Updating Travis' Qt version to 5.12 for QVariant::fromStdVariant.

We're already using C++17 features, so might as well move forward
and not do backward compativility if using new stuff implies zero cost.

AeonGames/AeonEngine,AeonGames/AeonEngine,AeonGames/AeonEngine,AeonGames/AeonEngine,AeonGames/AeonEngine