Back in the saddle! Heart containers, pausing, & NPCs

• health changes are animated now
• added heart containers
• added pause key, ESCAPE (no pause screen yet...)
• crafty now pauses on window blur, fixing a potential bug where
movement would become stuck on tab or application change
• added support for multi-statement dialogues
• added NPC sprites
• NPCs turn to face the player
• moved test chests to secret scene