Added a second video, showing how a normal level (without defense) looks like.
Added two new screenshot, showing a second controlable drone (there will be three different, with different energy and durability) and the configuration window.
There are two new items, which can be selected by the drone, a shield and a gravity gun, attracting objects.
The next steps will be:
- add a new enemy: a tank, which shoot cannonballs while driving toward the tower
- make the gravity gun placable in the world
