Add 27

27_collisionDetection/.gitignore
27_collisionDetection/LButton.c
27_collisionDetection/LButton.h
27_collisionDetection/LTexture.c
27_collisionDetection/LTexture.h
27_collisionDetection/LTimer.c
27_collisionDetection/LTimer.h
27_collisionDetection/Makefile
27_collisionDetection/collision.c
27_collisionDetection/common.c
27_collisionDetection/common.h
27_collisionDetection/dot.bmp

--
really did deep to sdl2 internal, and bunch of vim research.