[FIX] calendar: fix dates problems in some calendar view with timezones (days can't simply be calculated as 60 x 60 x 24 when modifiying a timestamp, because some days are longer or shorter due to DST (Daylight Saving Time) + remove useless 'm_weeks' function.
[FIX] calendar: fix dates problems in some calendar view with timezones (days can't simply be calculated as 60 x 60 x 24 when modifiying a timestamp, because some days are longer or shorter due to DST (Daylight Saving Time) + remove useless 'm_weeks' function.

git-svn-id: 79db53bec14f0ce9f7a86eb71e89624f126ad069@12525 b456876b-0849-0410-b77d-98878d47e9d5

changi67/tiki,oregional/tiki,changi67/tiki,tikiorg/tiki,tikiorg/tiki,oregional/tiki,tikiorg/tiki,oregional/tiki,oregional/tiki,changi67/tiki,tikiorg/tiki,changi67/tiki,changi67/tiki