Basic Pyxel application uses ~250MB of memory
### Is your feature request related to a problem? Please describe.
The following, basic Pyxel application takes around 250MB of memory (!)

```python
import pyxel

pyxel.init(256, 256, caption="TEST APP")

def update():
    if pyxel.btnp(pyxel.KEY_Q):
        pyxel.quit()

def draw():
    pyxel.cls(0)

pyxel.run(update, draw)
```

![memory_usage](https://user-images.githubusercontent.com/51701596/95501478-aa39c300-09a8-11eb-904c-536e9341142e.png)

That's pretty unexpected for such a minimalistic and tiny framework (which by the way is a great idea!) The equivalent in pygame uses less then 20MB.

It looks like the problem is caused by Recorder class. The following code instantiates 900 images with the size of screen (256x256 in my example):

```cpp
  for (int32_t i = 0; i < SCREEN_CAPTURE_COUNT; i++) {
    captured_images_[i] = new Image(width, height);
  }
```

And each image takes around 256KB (256 * 256 * 4 bytes):

```cpp
  data_[0] = new int32_t[width * height]();
```

So, in total it gives us **225MB (!)** (900 * 256KB)

### Describe the solution you'd like

It's pretty neat that Pyxel offers screen capture to GIF out-of-the-box. But to me it's more like a feature for developers, not players.
I'd love to have the possibility to turn off entire screen capture feature programatically during Pyxel initialization.
So, maybe we can have a new flag ```developer_mode``` in ```pyxel.init``` which will turn off recording subsystem:
```python
def init(
    width: int,
    height: int,
    *,
    caption: str = DEFAULT_CAPTION,
    scale: int = DEFAULT_SCALE,
    palette: List[int] = DEFAULT_PALETTE,
    fps: int = DEFAULT_FPS,
    quit_key: int = DEFAULT_QUIT_KEY,
    fullscreen: bool = False,
    developer_mode: bool = False
) -> None:
```

### Describe alternatives you've considered

Tbh I don't see any other **cheap** alternative solutions.

### Additional context
N/A
