Improve properties system

* Now works when you look from camera/driving a vehicle
* Fixed some issues with "Drive" property and cameras.
* Added language string for "Undone_KeepUpright"
* Removed undo from keep upright property. You are supposed to use
properties to disable keep upright.
Remove Undo_KeepUpright
Update properties.lua
Merge pull request #668 from robotboy655/properties

Improve properties system