Detect and auto-correct camera tilt
Follow-up of !102 (merged).
It would be good to detect and automatically correct tilts.
In the configuration file, we could add a new key in the same spirit of
tilt_correction = [auto|algo1|algo2|value]
autois the default automatic tilt computation method (it's up to us to decide which one)
algo2refer to tilt computation methods
valueis a scalar chosen by the user