Update - 0.519

[p]New Build 0.519 [/p]

• [p]Fix bug when build pieces are updating navmesh but have null sharedMesh, this could make it so you weren't able to cancel placing a piece when showing the preview,[/p]
• [p]Add "Delete Player Prefs" button to the Settings view in main menu - this will help some players that have issues with mouse or joystick mapping as it resets the registry data which isn't affected by the control mapping UI,[/p]
• [p]Fix null issue in popupmanager when used outside the gameplay manager,[/p]
• [p]Disable stone and thatch build pieces as those resources are not available in the demo[/p]