improved leap-frog tracking

corsika/detail/framework/geometry/LeapFrogTrajectory.inl

corsika/detail/framework/utility/CubicSolver.inl

corsika/detail/framework/utility/QuadraticSolver.inl

corsika/detail/framework/utility/QuarticSolver.inl

corsika/detail/modules/tracking/TrackingLeapFrogCurved.inl

corsika/detail/modules/tracking/TrackingLeapFrogStraight.inl

corsika/detail/modules/tracking/TrackingStraight.inl

corsika/framework/geometry/Intersections.hpp

corsika/modules/tracking/TrackingLeapFrogCurved.hpp

corsika/modules/tracking/TrackingStraight.hpp

examples/CMakeLists.txt

tests/framework/testProcessSequence.cpp

tests/framework/testSolver.cpp