New demo build v3.180723

• Added Immune Waves and Immune enemies - they have a sphere visual effect. Immune enemies can't be frozen and poisoned.
• Recreated multi-shot attack - now it's more handsome and powerful.
• Added the visual effect for splash attack.
• Added small tutorial - you can turn it on before start map.
• Added all towers for the "Humans" race. The whole race is ready!
• Added one more flying enemy - weak one-eye bat.
• Added new ground enemy - slow and strong Golem.
• Added the effect of pop-up coins when a creep dies.
• Update of costs and balance of towers.
• Changed map configuration.
• Minor fixes and updated.