Crash when using default Camera constructor - but pins not defined during build

[jonnor]

Hi,
after getting the build working and flashed (ref #1), I got a crash running the example code in the README file.

I narrowed it down to the camera = Camera() call. I suspect this happens because I did not use C defines for the pins (I like to keep the firmware builds as generic as possible).

Since I pass the pin configuration in Python, I could just remove this line and use just the explicit constructor. But it would be very good if this would just raise an exception instead of crashing :)