Version 0.8.5

Mechanics:

-Added the viking boss to the game

-Every boss unit can now summon minions

-The Spider can now climb walls, towers and gatehouses

Balancing:

-The mages cooldowns are now shorter but have increased mana cost
-Slightly increased the mages projectiles speed

Bugfixes:

-Added the eagle back to the game, it's AI is now fixed
-The button of the egg collector did show 0/1 at the beginning
-Units could be recruited before their building is finished
-Boss units didn't spawn at wave 10
-The knight and the soldier could hurt friendly units
-Workers did sometimes get stuck in walls after building them