transform.name does not roundtrip

[nden]

This demonstrates the problem:

rot=models.Rotation2D(23, name='rotation')
fa=AsdfFile()
fa.tree={'r': rot}
fa.write_to('rot.asdf')
frot=AsdfFile.read('todel.asdf')
frot.tree['r'].name is None
Out[38]: True

name is already part of the basic transform schema. Is there a way to add this to the general transform to_tree method instead of adding it to every subclass of TransformType?

[mdboom]

See #61.