Merge pull request #511 from unsignedzero/master

Added LaTeX German Reference Book
Sort sections and list
Add MySQL link to the index
Fix link
Merge pull request #512 from Robalni/master

Sort and add MySQL to index
Merge branch 'master' of github.com:unsignedzero/free-programming-books into unsignedzero-master
Correct README.md after d6e48c5
DSA: Annotated Reference with Examples -- new link
added some books
Merge pull request #514 from SuperStas/add-some-books

Added some books to russian version