no tildes in url. (RFC 3986)

replaced í with i in the url and it still takes me to the same place
even though my browser can interpret í, url_checker cannot do it
yet.
Merge pull request #888 from borgified/no_tildes_in_url_please

replaced í with i in a url (RFC 3986)
Adding Python interactive tutorial
Remove broken links
Added Practical Cryptography With Go

In a "Go" section
Merge pull request #889 from pericazivkovic/patch-1

Added Practical Cryptography With Go
Alphabetize Go section
Added egghead.io in free courses
Merge pull request #890 from emanuelsaringan/master

Added egghead.io in free courses
Update free-programming-books-pl.md

Added one free book on Prolog programming
Update free-programming-books.md

Added one book on CLP programming in Prolog
Merge pull request #892 from gakowalski/master

Adding book about Prolog CLP programming (English and Polish)
Add Vim Adventures to free-programming-interactive
Merge pull request #894 from rudylee/patch-1

Add Vim Adventures to free-programming-interactive
Added book made available by Alexandre Fiori
Merge pull request #895 from pmoranga/patch-1

Added book made available by Alexandre Fiori
Adds Polish HTML & CSS book
Sort list to alphabetical order
Merge pull request #896 from Bartuz/master

Adds Polish HTML & CSS book
Vim adventures : not free