Prepare app for handling of the second edition.
Refactor _view_source_script partial.
Replace html assets tags with rails assets helpers.
Remove useless (I hope) files.
Move custom css rules into the separate 'custom.css' file.
Add '?version=3.0' in each of relative paths across the whole translation of the first edition.
Add a translation of the Second Edition (slightly outdated - Rails version is 3.2.3).
Add missing images.
Fix bug in the show_origin script.
Update contents and preamble to the latest version of the 2nd edition.
Update first chapter of the 2nd edition to the latest version of the book.
Add missing image.
Fix typos.
Fix small bug in the show_origin script.
Add an origin of the second chapter of the 2nd edition.
Update second chapter of the 2nd to the latest version of the book.
Add translation of the second chapter's contents (2nd edition).
Fix typos.
Add missing image.
Upgrade Chapter 3 (2nd edition) to the latest book version.