small patch v1.0.2

- fixed the Steam turns leaderboard posting scores when losing (leaderboard will be cleared on update)
- lowered ROLLING ROCK max health from 1000 -> 100 so it can actually be destroyed
- you can now place buildings over allied units (although it will kill/remove them, unless you're building a farm)
- you can now UNDO your previous action
- new cast: RECONSTRUCT (4 hammers, repair 30 health of all buildings in a 3x3 tile area)
- made the first 6 waves a little bit easier so the difficulty curve isn't as steep anymore
- added a tooltip and some text in the tutorial that explains you need to survive 4 seasons in order to win
- optimized the game a little bit so it should be less laggy
- fixed a bug that gave enemy a very long health bar