Added some Danish ebooks (#3512)

* Danish programming books added

* Danish link to README

README.md

@@ -31,6 +31,7 @@ Please read [CONTRIBUTING](/CONTRIBUTING.md). If you're new to Github, [welcome]
 + [Burmese](/free-programming-books-mm.md)
 + [Chinese](/free-programming-books-zh.md)
 + [Czech](/free-programming-books-cs.md)
++ [Danish](/free-programming-books-dk.md)
 + [Dutch](/free-programming-books-nl.md)
 + [English](/free-programming-books.md)
 + [Finnish](/free-programming-books-fi.md)

free-programming-books-dk.md

+### Index
+
+* [C](#c)
+* [Java](#java)
+* [Pascal](#pascal)
+
+
+### C
+
+* [C - Programmering](http://synkro.dk/bog/c-programmering.pdf) - Henrik Kressner (PDF)
+* [Programmering i C](http://people.cs.aau.dk/~normark/c-prog-06/pdf/all.pdf) - Kurt Nørmark (PDF)
+
+
+### Java
+
+* [Objektorienteret programmering i Java](http://javabog.dk) - Jacob Nordfalk
+
+
+### Pascal
+
+* [Programmering i Pascal](http://people.cs.aau.dk/~normark/all-basis-97.pdf) - Kurt Nørmark (PDF)