Camera tracking: switch euclidean intersection code to use Ceres

Would not expect any significant changes in solver behavior, but
it could be more accurate in some cases.

Switching projective intersection to ceres is marked as a TODO
for now.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54880 954f8c5b-7b00-dc11-b283-0030488c597c
Camera tracking: support refining radial K1, K2 only

This commits adds extra refirenment entry in the menu which is
"K1, K2" and which will apparently refine only this distortion
coefficients.

This would be useful in cases when you know for sure focal length
(which could be obtained from lens, EXIF and so) but not sure
about how good you manual calibration is.

Be careful tho, there're no internal constraints on this
coefficients so distortion model could just screw up into insane
values.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54881 954f8c5b-7b00-dc11-b283-0030488c597c