* Added code for fast triangle-triangle intersection checking and function for fast detection of mesh self-intersections and mesh-to-mesh intersections withoug CGAL
* Fixed auto parameters in lambda helper function
* Replaced cbegin/cend with begin/end
* Fixed auto parameters in lambda helper function
* Added tests for igl::tri_tri_intersection_test_3d
* Added more tests, converted macros in Guigue2003_tri_tri_intersect.cpp to proper c++
* Renamed files and function names to follow IGL guidelines,
added reference to the original license for tri_tri_intersect