Merge branch 'squeeze/master'
Update foreword
Update chapter 1
Update chapter 2
Update chapter 3
Update chapter 7
Update chapter 4
Update chapter 12: RAID+LVM
Update chapter 12: Virtualization
Update chapter 12: Automated installation
Update chapter 12: Monitoring
Update chapter 12: Setting up RPM-based domUs (based on a suggestion by Thomas Goirand)
Update chapter 12: Mention SSDs
Fixed XML syntax
Add spanish translation for some automatic text of PDF version

Thanks to Matías Bellone <matiasbellone+debian@gmail.com>
Add lang attribute to the <book> entity for PDF/EPUB build

This allows tools like dblatex to properly translate automatic content
and to enable further localization related tweaks (like usage of babel
latex modules).
it-IT: updated Italian translations and Italian README file

Fixed Last-Translator in 03_existing-setup.po
Updated 07 thanks to Gabrielle Stilli
Updated Book_Info, 90_derivative_distributions, thanks to Paride Desimone
Added translation of 11 thanks to Giulio Turetta
de-DE: First version of chapter 10
de-DE: repaired one XML error in chapter 10
zh-CN: add 14_security.po, thanks to wing.W <dabouw@google.com>.