Version 0.20.0

Significant accuracy and quality improvements:

• Adjusted cross-correlation parameters to extract more data, and rely on the cross-check filter to remove errors and noise.
• Using matches from fundamental matrix to estimate image pose (improve performance and rely on more solid data than cross-correlation)
• Use a depth buffer to detect polygon obstruction and output rendered images (improves accuracy and significantly boosts performance)
• When merging track, average tracks instead of consuming them; by checking that all tracks follow the same direction, filter outliers
• Removed minimal angle filter (it's not as robust as it seemed originally)
• Fixed focal distance formula (it's supposed to use diagonals, not width)
• Adjust some parameters based on image size, to improve handling of larger images
• Removed requirements for points to be far apart in P3P
• Use point projections to build mesh (instead of original image) - as P3P and bundle adjustment can move cameras

Other changes:

• Better logging
• Option to limit number of points (avoid generating a mesh that doesn't fit into memory)
• Removed point normals, as they just used extra memory and caused artefacts in the macOS preview