0.9.020


 * Increased durability of shelter borders (marked with stars) against the monsters attacks.
 * Wooden spikes don’t slow down monsters like fences now. They block monsters movement and inflict some damage.
 * Dwarves-mages can use lightning spell unlimited times between fireball spells.
 * Added new items which increase skills efficiency. You should place these items into special equipment slot.
 * Dwarves now improve their skills by doing particular job.
 * Added 2 backpacks which increase dwarves capacity by 1 and 2 pieces.
 * Portal spell exit now always opens near the main stockpile.
 * You gains significant XP if destroys all monsters in the wave.
 * XP bonus for killing a monster now depends on its health.
 * Improved algorithm of calculating shelter borders considering doors inside the shelter.
 * Changed number of log bridges crafting at a time.
 * Fixed elevator tunnels intersections.
 * Fixed frostlings attack errors.
 * Improved archers AI to prevent attack of underground ghost. If archer misses several times then attack task cancels for him.
 * Fixed bug with XP while changing back wall blocks.
 * Fixed bug with tornado destroying brick walls.
 * Fixed bug with crystals growing over constructions.
 * Fixed bug with giant worm which can destroy blocks under additional stockpiles.
 * Fixed some crash issues.