Added missing functions

[Iskander0]

GetWindowHandle GetWorldToScreenEx LoadFileData SaveFileData LoadFileText SaveFileText FileExists DirectoryExists IsFileExtension GetFileExtension GetFileName GetFileNameWithoutExt GetDirectoryPath GetPrevDirectoryPath GetWorkingDirectory ChangeDirectory GetFileModTime OpenURL SetGamepadMappings <- fixed name

[gen2brain]

Thanks, I would prefer not to add file/dir functions that are all available in the standard Go library. Also, no need for SetRandomSeed. This makes maintenance easier for future raylib renames etc. Cursor functions used to go in the platforms file, they needed to be there, probably not the case anymore.

Can you just add

GetWindowHandle GetWorldToScreenEx OpenURL SetGamepadMappings

[gen2brain]

Thanks, I hand-picked some functions and added them.