Added OOP - Learn Object Oriented Thinking & Programming
Added a couple of database, datamining and information retrieval books
Update free-programming-books.md

Add http://gitimmersion.com/
Update free-programming-books.md

Added Open Government; Collaboration, Transparency, and Participation in Practice by Daniel Lathrop, Laurel Ruma: O'reilly Media
Merge pull request #277 from tomplee/patch-1

Added OOP - Learn Object Oriented Thinking & Programming
Merge pull request #278 from canibanoglu/database-books

Added a couple of database, datamining and information retrieval books
Merge pull request #279 from alessgerman/patch-1

Update free-programming-books.md
Merge pull request #280 from pasanwijesinghe/master

Update free-programming-books.md
Added 4 Free Java Books
Merge pull request #281 from aliemre/master

Added 4 Free Java Books
add SF, CPDT, and Agda tutorial
fix Agda tutorial's title
Merge pull request #282 from philnguyen/master

Add Coq and Agda books