Fix bug where arrays with dict displayed wrong

When executing the following code:

    import pyaml
    import collections
    m = {'items': [{"template": "test", "otherval": "test2"}, {"group": "group1", "test2": "test"}]}
    v = {"t": [1 , 3, 4 ], "xxx" : m, 'zzz': {"testing": "testing", "bal": "test"}}
    k = collections.OrderedDict(v)
    print pyaml.dump(k)

This outputs an invalid yaml that should be valid. The pull request fixes this.