Separated langpack, concept art for inventory UI

Former-commit-id: 7a98df93b4ef50b47283abcd99576d6fbefc9cc5
Former-commit-id: db6e34417ccf84e59ba68547f30459cb4b188eb7

src/net/torvald/terrarum/GAME_SYSTEM.md

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+The game has elements that are:
+
+- Actors
+    - Controller
+        - AI
+        - JInput (Provided by LWJGL)
+    - Factioning
+    - Scheduler
+    - Physics solver (simple, AABB-oriented)
+    - _TODO: sprite assembler (character--avatar--maker)_
+- Imagefont
+    - Font drawer
+        - Hangul character assembler (aka JOHAB)
+- Sprite animator (really simple one)
+- De/serialiser
+- Concurrency helper (really simple one)
+- Tiles
+    - Tile property database
+- Items
+    - Item property database
+        - _TODO: Material system_
+- Map drawer
+    - Map camera
+    - Map drawer
+    - Lightmap renderer
+- Map generator
+    - Utilises Joise Modular Noise Generator
+    - Additional noise filters
+- Real estate
+    - The registry (a book that records the current owner of tiles on the map. Owner can be a single NPC or faction)
+    - Utility
+- Internationalisation
+    - Language pack
+
+The elements are connected like:
+
+- Actors
+    - Controller ← AI, Player Input
+    - AI ← Factioning, Scheduler
+    - class "Actor"
+        - class "ActorWithBody"
+            with properties like (AIControlled, Factionable, Luminous, Visible, etc.)
+            - class "NPCIntelligentBase"
+                - (NPCs that has AI and can be interacted)
+            - (fixtures, player)
+        - (any of the invisible actors)
+        
+