Changes on Lights

- adjusted lights so they are called to do something, instead of it 
being handled on game world 
- lights has only coordinate arguments + a table with all other optional 
ones.
- renamed a lot of lights components to radius instaed of range, as it 
was agreed before elsewhere

data/shaders.lua

@@ -2,7 +2,7 @@ shader = {}
 shader.circle_gradient = love.graphics.newShader[[
 	uniform float pos_x;
 	uniform float pos_y;
-	uniform float range;
+	uniform float radius;
 	uniform float scale;
 
 	vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 screen_coords ){
@@ -12,11 +12,13 @@ shader.circle_gradient = love.graphics.newShader[[
 		float distance_x = pos_x - screen_coords.x / scale;
 		float distance_y = pos_y - screen_coords.y / scale;
 		float distance = sqrt( pow(distance_x,2) + pow(distance_y,2) ) ;
-		if (distance < range){
-			float alpha = 1-(5*distance/range);
+		if (distance < radius){
+			float alpha = 1-(5*distance/radius);
 			if (pixel.a > alpha){
 				pixel.a = alpha;
 			}
+		}	else {
+			pixel.a = 0;
 		}
 		return pixel * color * color;
 	}