Allow lxml 3.5 in setup.py and tox

After a short discussion on IRC about "is XML a terrible mistake?" it
appears that there is a new version of lxml 3.5 that is compatible with
this project.

In fact, I'm quite sure any version of lxml < 4.x will work fine.

Also, tox results show me that Python 2.7 with any version of lxml
works fine too. What a wonderfull world?

Thank you @mrjmad for the request! ;-)

Author: Exirel

setup.py

@@ -31,7 +31,7 @@ def read(*parts):
 ]
 
 setup(name='xmlunittest',
-      version='0.3.1',
+      version='0.3.2',
       description='Library using lxml and unittest for unit testing XML.',
       long_description=read('README.rst'),
       author='Florian Strzelecki',
@@ -40,5 +40,5 @@ def read(*parts):
       url='http://python-xmlunittest.readthedocs.org/en/latest/',
       py_modules=['xmlunittest'],
       test_suite="test",
-      install_requires=['lxml>=2.3,<=3.4.4'],
+      install_requires=['lxml>=2.3,<4.0.0'],
       classifiers=classifiers)

tox.ini

@@ -1,11 +1,13 @@
 [tox]
-envlist = py27, py34
+envlist = py27-lxml{30,34,3x}, py34-lxml{30,34,3x}
 
 [testenv]
 
 commands =
     py.test test.py
 
 deps =
-    lxml==3.0
-    pytest==2.6.4
+    lxml30: lxml>=3.0,<3.1
+    lxml34: lxml>=3.4,<3.5
+    lxml3x: lxml<4.0
+    pytest