Added E-Books Directory to Meta-Lists

Site contains a good deal of free books on a wide variety of subjects.

free-programming-books.md

@@ -111,6 +111,7 @@
 ###Meta-Lists
 * [25 Free Computer Science Ebooks](http://www.coderholic.com/25-free-computer-science-books/)
 * [Cheat Sheets (Free)](http://refcardz.dzone.com/)
+* [E-Books Directory](http://www.e-booksdirectory.com/)
 * [Free Smalltalk Books, collected by Stéphane Ducasse](http://stephane.ducasse.free.fr/FreeBooks.html)
 * [Free Tech Books](http://www.freetechbooks.com/)
 * [Hacker Shelf](http://hackershelf.com/browse/)