Organize geometry and add SBC15

algorithms/geometry/circle.cpp

algorithms/geometry/convex_hull.cpp

algorithms/geometry/point.cpp

algorithms/geometry/polygon.cpp

algorithms/geometry/primitives.cpp

algorithms/geometry/rotating_calipers.cpp

algorithms/geometry/segment.cpp

contests/Cadernaveis/LA5138.cpp

contests/SBC15/A.cpp

contests/SBC15/B.cpp

contests/SBC15/C.cpp

contests/SBC15/D.cpp

contests/SBC15/E.cpp

contests/SBC15/F.cpp

contests/SBC15/J.cpp

contests/SBC15/K.cpp