setup.py: Require pytest>=2.6, declare Python 3.5 compatibility

setup.py

@@ -26,11 +26,11 @@ def _get_version():
       author_email='eisensheng@mailbox.org',
       url='https://github.com/eisensheng/pytest-catchlog',
       py_modules=['pytest_catchlog', ],
-      install_requires=['py>=1.1.1', ],
+      install_requires=['py>=1.1.1', 'pytest>=2.6'],
       entry_points={'pytest11': ['pytest_catchlog = pytest_catchlog']},
       license='MIT License',
       zip_safe=False,
-      keywords='py.test pytest',
+      keywords='py.test pytest logging',
       classifiers=['Development Status :: 4 - Beta',
                    'Intended Audience :: Developers',
                    'License :: OSI Approved :: MIT License',
@@ -41,6 +41,7 @@ def _get_version():
                    'Programming Language :: Python :: 3.2',
                    'Programming Language :: Python :: 3.3',
                    'Programming Language :: Python :: 3.4',
+                   'Programming Language :: Python :: 3.5',
                    'Programming Language :: Python :: Implementation :: CPython',
                    'Programming Language :: Python :: Implementation :: PyPy',
                    'Topic :: Software Development :: Testing'])