add STMEntityController

#137
intermediate commit
intermediate commit
intermediate commit
finish stc.entity in core data

closes #137
remove unnecessary comments
remove code duplicate
prevent STMEntity duplicate
skip entity with nil url
new way to flushing objects
Merge branch 'dev' into stc.entity
addButton
addButton delegate
addPartnerPopover
show popover in centre after rotation
cancelButtonPressed
make separate class for popoverNC & popoverVC
segue to addOutlet
textFields delegate
add partner and outlet