Refactor for nicer test setup.

``python setup.py test`` works out of the box.
Added tox.ini.

MANIFEST.in

@@ -0,0 +1,3 @@
+include CHANGES.txt
+include README.rst
+include README.txt

setup.py

@@ -24,30 +24,33 @@
 long_description = "\n\n".join((README, CHANGES))
 long_description = long_description.decode('utf-8')
 
-install_requires =[
+requires = [
     'setuptools',
     'Chameleon >= 2.7',
     'zope.interface',
     'zope.component',
     'zope.configuration',
-    'zope.testing',
     'pyramid >= 1.4',
     'pyramid_zcml >= 0.9.2',
     ]
 
-tests_require = []
+docs_extras = [
+    'Sphinx',
+    'docutils',
+    'repoze.sphinx.autointerface']
+
+testing_extras = [
+    'manuel',
+    'coverage',
+    'nose',
+    'zope.testing>3.8.7',
+    'zope.component>3.9.2']
 
 if sys.platform == "darwin":
-    tests_require.append("MacFSEvents")
+    testing_extras.append("MacFSEvents")
 
 if sys.platform.startswith("linux"):
-    tests_require.append("pyinotify")
-
-tests_require = install_requires + [
-    'manuel',
-    'zope.testing>3.8.7',
-    'zope.component>3.9.2',
-    ] + tests_require
+    testing_extras.append("pyinotify")
 
 setup(name='pyramid_skins',
       version = '1.1',
@@ -75,10 +78,11 @@
       namespace_packages=[],
       include_package_data = True,
       zip_safe = False,
-      install_requires=install_requires,
-      tests_require = tests_require,
-      extras_require = {
-        'tests': [dep.split('==')[0] for dep in tests_require],
-          },
+      install_requires=requires,
+      tests_require=testing_extras,
+      extras_require={
+          'testing': testing_extras,
+          'docs': docs_extras,
+          'development': testing_extras + docs_extras},
       test_suite="pyramid_skins.tests",
       )

tox.ini

@@ -0,0 +1,13 @@
+[tox]
+envlist =
+    py27,pyramid14
+
+[testenv]
+commands =
+    pip install pyramid_skins[testing]
+    nosetests
+
+[testenv:pyramid14]
+basepython = python2.7
+deps =
+    pyramid>=1.4,<1.5