3.0 seems like an appropriate time to do that.

Conflicts:
	modules/core/include/opencv2/core/types_c.h
	modules/gpu/src/cuda/imgproc.cu
	modules/gpu/src/cuda/safe_call.hpp
	modules/gpu/src/error.cpp
	modules/gpu/src/imgproc.cpp
	modules/imgproc/src/distransform.cpp
	modules/imgproc/src/shapedescr.cpp
	modules/python/src2/cv2.cpp
	modules/python/src2/cv2.cv.hpp

Update on the class to reflect the review. Split the class into virtual and implementation. change of name to LineSegmentDetector, using Input/Output-Arrays, general clean ups.

Suggested by @SpecLad