Fix timezone error

Javacript Date() is using UTC time. However the time
given by yr.no is in the city local timezone and should
be used as it.

Now retrieve the offset between the UTC time and the device
local time to correct the time accordingly.

Change-Id: Ib95bba390a890cbef57c55c950440e253ba6f380
Reviewed-by: Andrew Knight <andrew.knight@digia.com>