fixed non-initialization bug for dc->gamma

pdf.c

@@ -86,6 +86,7 @@ static int newDrawContext(lua_State *L) {
 	dc->zoom = zoom;
 	dc->offset_x = offset_x;
 	dc->offset_y = offset_y;
+	dc->gamma = gamma;
 
 	luaL_getmetatable(L, "drawcontext");
 	lua_setmetatable(L, -2);

reader.lua

@@ -159,12 +159,6 @@ function setzoom(cacheslot)
 	if optarg["G"] then
 		print("gamma correction: "..optarg["G"])
 		cache[cacheslot].dc:setGamma(optarg["G"])
-	else
-		-- there's still a bug in the DC initialization in C code,
-		-- so we disable gamma correction here explicitly
-		-- (it should be disabled by default)
-		-- TODO: correct bug in C API
-		cache[cacheslot].dc:setGamma(-1.0)
 	end
 end