carriage return differs in tree copy

[Thomas Steinacher]

OS X 10.11.4
Python : sys.version_info(major=2, minor=7, micro=10, releaselevel='final', serial=0)
lxml.etree : (3, 6, 0, 0)
libxml used : (2, 9, 2)
libxml compiled : (2, 9, 2)
libxslt used : (1, 1, 28)
libxslt compiled : (1, 1, 28)

After copying the LXML tree with copy.copy (or copy.deepcopy), I am getting a tree that renders differently. I would expect both trees to render the same way.

In [1]: import lxml.html

In [2]: import copy

In [3]: tree = lxml.html.fromstring('<div>\r</div>')

In [4]: lxml.html.tostring(tree)
Out[4]: '<div>\r</div>'

In [5]: lxml.html.tostring(copy.copy(tree))
Out[5]: '<div>&#13;</div>'

[scoder (scoder)]

Yes, that seems wrong. Might be an issue with the configuration of the underlying "xmlDoc", probably with the document encoding that it specifies.
PR welcome.