Update CSFML version to 2.6.1

Update CSFML to 2.6.0

Update CSFML version to 2.5.2

Update CSFML version to 2.5.1

- Add macOS build script
- Update existing nuget build script

Merge pull request #130 from DemoXinMC/master

sfText_getLineSpacing is not properly declared in Text.h

Merge pull request #120 from crumblingstatue/master

Add setVirtualKeyboardVisible

Merge pull request #75 from SFML/feature/2.3_prep

Bumped version number to 2.3 and updated readme.txt

Merge pull request #53 from eXpl0it3r/feature/version_2.2

Updated CSFML's version to 2.2.0.

Updated version number

Updated the website links in readme.txt