Further work on MasterSchedule

Need to test the system:
a) test
1. import 2013
2. import 2014

b) test
1. import 2013
2. import another 2013

c) test
1. import 2014
2. import another 2014

See what is wrong with not deleting
master_schedule_week_notes on same GUID (possible bug)

Reported-by: Matija Baric
Signed-off-by: Matija Baric <matija.baric@gmail.com>