Turn off debug output

At some point would be nice to turn off the debug output - or make optional. It's useful stuff, so not suggesting just deleting.

```python
>>> pycam = adafruit_pycamera.PyCamera()
FutureWarning: FourWire moved from displayio to fourwire
FutureWarning: Display moved from displayio to busdisplay
FutureWarning: Display renamed BusDisplay
reset camera
pre cam @ 0.333008
I2C addresses found: ['0x19', '0x58']
Found AW9523
sdcard done @ 0.399414
Initializing camera
Found camera OV5640 (240 x 176) at I2C address 3c
camera done @ 1.19922
['__class__', '__enter__', '__exit__', 'address', 'ae_level', 'aec2', 'aec_value', 'agc_gain', 'awb_gain', 'bpc', 'brightness', 'colorbar', 'contrast', 'dcw', 'deinit', 'denoise', 'exposure_ctrl', 'frame_available', 'frame_size', 'framebuffer_count', 'gain_ceiling', 'gain_ctrl', 'grab_mode', 'height', 'hmirror', 'lenc', 'max_frame_size', 'pixel_format', 'quality', 'raw_gma', 'reconfigure', 'saturation', 'sensor_name', 'sharpness', 'special_effect', 'supports_jpeg', 'take', 'vflip', 'wb_mode', 'whitebal', 'width', 'wpc']
colors 16777215
colors 16777215
init done @ 2.13428
>>>
```

首先定位负责显示初始化、计时、I2C 和颜色消息的 PyCamera 源代码；issue 中未指定文件或测试。确定如何在保留有用诊断信息的同时禁用调试输出或使其成为可选项，然后验证在关闭调试输出时正常的相机初始化仍能工作，并且在启用调试输出时仍可使用。

由索引模型根据 Issue 内容生成。