new mail backend
code cleanup
i18n
news as newsletter,
database update:
alter table BuLiTippApp_news add column newsletter bool; 
alter table BuLiTippApp_user add column receive_newsletter bool;
update BuLiTippApp_user set receive_newsletter = 1;
fix for statistics refresh
customizable reminder offset, closes #29.
syncdb, update crontab

create table BuLiTippApp_user_reminder_offset (id integer PRIMARY KEY,
user_id integer, reminderoffsets_id integer);

insert into BuLiTippApp_reminderoffsets (value) values(0), (1), (2),
(3), (4), (5 );

insert into BuLiTippApp_user_reminder_offset (user_id,
reminderoffsets_id)
	select user_ptr_id, 2 from BuLiTippApp_user
;
insert into BuLiTippApp_user_reminder_offset (user_id,
reminderoffsets_id)
	select user_ptr_id, 4 from BuLiTippApp_user
;