Added OpenSCAD User Manual

free-programming-books.md

@@ -48,6 +48,7 @@
 * [Oberon](#oberon)
 * [Objective-C](#objective-c)
 * [OCaml](#ocaml)
+* [OpenSCAD](#openscad)
 * [Oracle Server](#oracle-server)
 * [Oracle PL/SQL](#oracle-plsql)
 * [Parrot / Perl 6](#parrot--perl-6)
@@ -577,6 +578,11 @@
 * [Think OCaml](http://web.archive.org/web/20120307164444/http://www.thinkocaml.com/)
 
 
+###OpenSCAD
+
+* [OpenSCAD User Manual](http://en.wikibooks.org/wiki/OpenSCAD_User_Manual)
+
+
 ###Oracle Server
 
 * Oracle's [Guides and Manuals](http://tahiti.oracle.com/)