public / sequelize

fix options priority (add to #315)

This reverts commit bfbd3f1a.

It makes some test fail

Replaced Utils.merge with Utils._.extend

This gives better results when doing an update so you don't
run into issues where you did something like:

mymodel.myfield = 'foo'
mymodel.save(theseParams)

mymodel.myfield of course wasn't updated, but it will appear
to a test perhaps that it was.

This will also allow the attributes that are returned to behave the same
as they would in an insert or a select query.  To see this try creating
an ARRAY column type in postgres, then make it a text field in
sequelize.  The value that will be returned is the same on the type for
insert/select but not for update.