v_0.81 Demo Update

[b]Update[/b] Added floor bonuses and tooltip display Replaced battlefield images Modified some tutorial messages (added obstacle removal section) Fixed unit slot indices not resetting when loading games Changed dates and conditions for some events Added new events Adjusted tooltip UI size to fit text [b]Bug Fixes[/b] Fixed an issue where loading from auto-save slot would resume paused time Changed game to continue running when in background