fix for static builds with mingw-w64 compilers - part 1
fix for static builds with mingw-w64 compilers - part 2
Merge pull request #218 from BMBurstein/master

fix for static builds with mingw-w64 compilers
Added x64 binaries for MinGW and adapted the CMake file.
Merge pull request #356 from eXpl0it3r/master

Added external libraries for MinGW x64 compilers
Added source file groups in CMake files (for better organization of sources when opening SFML projects in IDEs)
Fixed: outline direction were depending on the order in which points were defined in a Shape