BUG when start dt is a monday:

Monday to Monday

>>> from xix.utils.timetool import setDayOfWeek, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY
>>> from time import strptime, strftime, mktime, tzset
>>> from datetime import datetime
>>> t = strptime('2005-11-28', '%Y-%m-%d')
>>> dt = datetime.fromtimestamp(mktime(t))
>>> dt2 = setDayOfWeek(dt, MONDAY, startsun=True)
>>> print strftime('%Y-%m-%d', dt2.timetuple())
2005-11-28


Monday to Tuesday

>>> dt2 = setDayOfWeek(dt, TUESDAY, startsun=True)
>>> print strftime('%Y-%m-%d', dt2.timetuple())
2005-11-29


Monday to Wednesday

>>> dt2 = setDayOfWeek(dt, WEDNESDAY, startsun=True)
>>> print strftime('%Y-%m-%d', dt2.timetuple())
2005-11-30

Monday to Thursday


>>> dt2 = setDayOfWeek(dt, THURSDAY, startsun=True)
>>> print strftime('%Y-%m-%d', dt2.timetuple())
2005-12-01

Monday to Friday


>>> dt2 = setDayOfWeek(dt, FRIDAY, startsun=True)
>>> print strftime('%Y-%m-%d', dt2.timetuple())
2005-12-02

Monday to Saturday

>>> dt2 = setDayOfWeek(dt, SATURDAY, startsun=True)
>>> print strftime('%Y-%m-%d', dt2.timetuple())
2005-12-03


