Draw and scroll the map.

1. Draw and scroll the map to the end.
2. Add linux Makefile, make sure you install SDL2,SDL2_Image and
zlib if you want to compile the code. Folder "include" and "lib"
are not necessary in Linux environment. They work for VS2010.
3. It's very easy to make cross-platform game with SDL, I write
and test code in VS2010 at home, compile and test in Ubuntu at
work's free time.