Extensions and explicit types

Added a new "RaylibExtensions" static class that gives overloaded extension methods to types so you can use them directly instead of calling the raylib class for everything.

Two new types: "Circle" and "Line"

All the "var" variables were changed to explicit types on the raylib class.

"MakeDirectory" overload, and string version of "GetApplicationDirectory" and "GetWorkingDirectory" methods.

Raylib-cs/types/native/AnsiBuffer.cs

@@ -1,5 +1,5 @@
-using System;
 using System.Runtime.InteropServices;
+using System;
 
 namespace Raylib_cs;