df.iteritems() should yield Series even with non-unique column labels

df=DataFrame([[1,2,3],[4,5,6]],columns=['a','a','b'])
for k,v in df.iteritems():
    self.assertEqual(type(v),Series)

[lodagro]

see also #2047

Thank you, I missed that and was unaware of df.icol()

#2228, #2227 make icol unsuitable right now, though it's the natural mechanism to use.