Update CSFML version to 2.5.1

- Add macOS build script
- Update existing nuget build script

CMakeLists.txt

@@ -22,7 +22,7 @@ include(${CMAKE_SOURCE_DIR}/cmake/Config.cmake)
 # setup version numbers
 set(VERSION_MAJOR 2)
 set(VERSION_MINOR 5)
-set(VERSION_PATCH 0)
+set(VERSION_PATCH 1)
 
 # add the CSFML header path
 include_directories(${CMAKE_SOURCE_DIR}/include)