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- Fix for reading grease pencil data for movie clips.
- Request from Francois: undistort grease pencil to allow
manual calibration.
Only strokes made in "Cursor" space are getting undistorted,
strokes made in view space are kept unchanged.
This allows to make such workflow of manual calibration:
- Outline straight line in footage with GP.
- [Optional] mute footage.
- Enable Display->Manual Calibration.
- Tweak distortion coefficients until you'll like result.
- [Optional] Use strokes made in viewspace to help checking
of straightness of outlined features.
Not ideal but could be nice addition for grid-only calibration
until proper tools are getting ported to libmv/blender.
f403102736