Update to version 1.2 - Animated Items and Heroes

First update related to simple 2-frame animation. 

• Added animated items sheet with transparency - new directory [Animated]
• Added animated heroes sheet with transparency - new directory [Animated]
• Added a few more pipeline tiles
• Replaced one of the ladder tiles with a staircase going up
• Added more tileset colour variants
• Added new elevation type to the [Tileset:Walls]
• Added arms-up pose and defeated sprites for [Heroes]
• Added more variants of Big Crowmen and moved them to [Monsters] instead of [UI Elements]
• Added a new cat [NPC]