Added OCaml playground (#3067)

* Added OCaml playground

* delint

free-programming-playgrounds.md

@@ -12,6 +12,7 @@
 * [Kotlin](#kotlin)
 * [.Net](#dotnet)
 * [Node.js](#nodejs)
+* [OCaml](#ocaml)
 * [Perl](#perl)
 * [PHP](#php)
 * [Python](#python)
@@ -91,6 +92,11 @@
 * [Ideone](http://ideone.com)
 
 
+### OCaml
+
+* [Try OCaml](https://try.ocamlpro.com)
+
+
 ### Perl
 
 * [Perl](http://tryperl.pl)