added char attributes, enemies, combat

I used the strategy/movement system for NPCs from Beast and added
in some of my own mechanics for melee and projectile combat. A leveling
system has also been established which modifies damage as the player
levels up. Next order of business is level design, monster spawning, and
game progression.

projectile.py

@@ -0,0 +1,53 @@
+from retro.game import Game
+
+class Projectile:
+    character = "*"
+    deadly = False
+        
+    def __init__(self, position, direction, speed, game):
+        self.position = position
+        self.direction = direction
+        self.speed = speed
+        if game.get_agent_by_name("player").class_ == "Rogue":
+            if self.direction in [(1,0), (-1,0)]:
+                self.character = "-"
+            elif self.direction in [(0,1), (0,-1)]:
+                self.character = "|"
+
+    def move(self, game):
+        """Try to move in direction set by player when launched. If blocked,
+        disappear."""
+        dx, dy = self.direction
+        new_position = (self.position[0] + dx, self.position[1] + dy)
+        if game.on_board(new_position):
+            if game.is_empty(new_position):
+                self.position = new_position
+            else:
+                agent = self.get_agent_in_position(new_position,game)
+                if agent:
+                    if agent.deadly:
+                        agent.hp -= game.get_agent_by_name("player").damage
+                        game.remove_agent(self)
+                    else:
+                        game.remove_agent(self)
+        else:
+            game.remove_agent(self)
+
+    def play_turn(self,game):
+        if game.turn_number % self.speed == 0:
+            self.move(game)
+
+    def get_agent_in_position(self, position, game):
+        """Returns an agent at the position, or returns None. 
+        game.get_agents_by_position always returns a list, which may
+        contain zero, one, or multiple agents at the given position. 
+        In the Beast game, we never allow more than one agent to be in 
+        a position.
+        """
+        agents = game.get_agents_by_position()[position]
+        if agents:
+            return agents[0]
+
+    def handle_collision(self, game):
+        # need to fix this at some point
+        pass