Restore lessons operations
Fix gitignore
Delete build dir from repo
Added point_in_convex_polygon operation
Fix wrong-restored segments_intersect
Added some tests to rect_segment and fix small bug
Push not-pushed test
Contour class refactored
fat commit

[+] some operations. I'll push some interfaces, pull implementation for
them
[+] triangle_contains_point example
[+] bug fixes
Merge branch 'contour_fix'
Merged with main branch
Some fixes in merged branch
merge commit
merge commit