Unify row highlight CSS. Apply row highlight to users list.
Translate 'similarity' page
Connect labels to checkboxes on 'similarity' page
Display city in the users list
Translate 'users' page
Always quote option text in html.tti
Use loop variables in 'problems' template

Remove duplicates of globals required by HTML::Template.
Use loop variables in 'problems_retest' template
Use loop.parity from Template Toolkit
Translate 'contest_params' page
Translate 'user_stats' page
Translate 'send_message_box' page
Translate 'envelope' page
Improve paging

* Refactor, use 'min' and 'max' functions.
* Display previous and next page numbers whenever possible.
* Display last visible page if requested page number is too large.
Allow to search multiple values in lists