Added brazillian book about RegEx
Added C language book
Merge pull request #1217 from drgarcia1986/master

Added brazillian book about RegEx
Merge pull request #1218 from WizuO/master

Added C language book in Swedish
Merge pull request #1216 from grogy/cs-books

Added czech book about webdesign
Added PHP book, fixed formatting
Added Codility to interactive tutorials