Changed easings to a direct port

- Trying direct ports of modules starting with easings.
- Readme fix and removed old rlgl.
- Improving documentation.

Bindings/Raymath.cs

@@ -1,3 +1,11 @@
+/* Raylib-cs
+ * Raymath.cs - Core bindings to raymth
+ * Copyright 2019 Chris Dill
+ *
+ * Release under zLib License.
+ * See LICENSE for details.
+ */
+
 using System;
 using System.Runtime.InteropServices;