Added Modules Mensa and Updates

Module Mensa keeps the info about the menu
(url, format, filename and mime)

Module Updates extracts the list of timemodify values.
Added UsiDB module
Switched to the standard mssql_connect() interface

Switched to the standard mssql_connect() interface.
The PDO driver for GNU/Linux is still experimental and the
Kurogo db_mssql is meant to work only on Windows platform so
the standard mssql_connect() interface is the only alternative.
Added get_version method to usidb webservice
Bugfix in the usidb->raiseError() messages
Added the TeachingTimetables and Updates modules

The Updates module extracts a list of hash values. Every hash
value is a content version indicator. This allows the mobile app
to distinguish between the new and old content. The mobile app will
then request for the content only if the new content is available.

The TeachingTimetables module uses the database for the static
content also available on the faculty sites. Having the content
inside the db is more robust. No html parsing needed.
Added the database structure
Added courses module and usidb class + refactoring

Added courses module and usidb class. The configuration of usidb
lib is in the config/site.ini file.

Refactored updates and usinews modules.
Added AcademicCalendar and Examination Timetables

Added AcademicCalendar support
Added Examination Timetables support
Updated the database_structure.sql file
Added usipeople module.

Added usipeople module.
The hash calculation is now done inside the sqlserver in order
to minimize the data traffic.
Updated the database_structure.sql file.
Added USI Sport module