marked error_screen as a protected module, added --dev launch option

pocket_friends/_development/surfaces/_error_screen.py

@@ -0,0 +1,28 @@
+import pygame
+from pocket_friends.elements import surface
+
+
+class Surface(surface.GameSurface):
+    def __init__(self, game_res, resources_dir, game_fps, **kwargs):
+        super().__init__(game_res, resources_dir, game_fps)
+        self.frames = 1
+        self.game_fps = game_fps
+        self.delay = 1
+        self.font = pygame.font.Font(resources_dir + '/fonts/5Pts5.ttf', 10)
+        self.title = pygame.image.load(resources_dir + '/images/debug/invalid.png').convert_alpha()
+        self.next_surface = 'title'
+
+    def update(self):
+        self.preprocess()
+
+        self.blit(self.title, (0, -4))
+        text = self.font.render('Frames: {0}'.format(self.frames), False, (64, 64, 64))
+        self.blit(text, (3, 68))
+
+        self.frames += 1
+        self.frames %= self.game_fps
+
+        for event in pygame.event.get():
+            if event.type == pygame.KEYDOWN:
+                if event.key == pygame.K_b:
+                    self.running = False