Wing Feathers tweak

[DreadKnight]

Scavenger could once more fly over any creatures / obstacles / traps by default, while the upgrade could allow the unit to stack unused movement points (maybe up to a certain cap), allowing a well rested Scavenger to really do wonders on the battlefield strategy wise, allowing you to pretty much rearrange all the units as you please, kinda like a buffed version of the Strategy skill from HoMM3 game.