better reference point
better output and filtering

colorful mode for easier filter creation
special handling for partially obscured lines
extra lines can be added
Merge branch 'master' of https://github.com/jreinhardt/perspective-undistorter
Merge branch 'master' of https://github.com/jreinhardt/perspective-undistorter
comments in filter files are now possible
better size for output

the calculation now ignores filtered points