setup.py, tox.ini: move nose/rednose from install deps to test deps

Remove nose/rednose from `setup_requires` and instead declare them in
`tests_require`. Also explicitly add `nose` and `rednose` to
dependencies list in tox.ini (to avoid breaking test runs).

`python setup.py nosetests` is the preferred way for running tests, and
this works, except that placing test deps (nose/rednose) in the
`setup_requires` also means that these dependencies are pulled in for
installs of mongoengine. These deps are not actually be required just
to run mongoengine, so setup.py should not force users to install these
dependencies.

This refactoring should not change any test run semantics.

setup.py

@@ -52,13 +52,13 @@ def get_version(version_tuple):
 extra_opts = {"packages": find_packages(exclude=["tests", "tests.*"])}
 if sys.version_info[0] == 3:
     extra_opts['use_2to3'] = True
-    extra_opts['tests_require'] = ['nose', 'coverage==3.7.1', 'blinker', 'Pillow>=2.0.0']
+    extra_opts['tests_require'] = ['nose', 'rednose', 'coverage==3.7.1', 'blinker', 'Pillow>=2.0.0']
     if "test" in sys.argv or "nosetests" in sys.argv:
         extra_opts['packages'] = find_packages()
         extra_opts['package_data'] = {"tests": ["fields/mongoengine.png", "fields/mongodb_leaf.png"]}
 else:
     # coverage 4 does not support Python 3.2 anymore
-    extra_opts['tests_require'] = ['nose', 'coverage==3.7.1', 'blinker', 'Pillow>=2.0.0', 'python-dateutil']
+    extra_opts['tests_require'] = ['nose', 'rednose', 'coverage==3.7.1', 'blinker', 'Pillow>=2.0.0', 'python-dateutil']
 
     if sys.version_info[0] == 2 and sys.version_info[1] == 6:
         extra_opts['tests_require'].append('unittest2')
@@ -79,6 +79,5 @@ def get_version(version_tuple):
       classifiers=CLASSIFIERS,
       install_requires=['pymongo>=2.7.1'],
       test_suite='nose.collector',
-      setup_requires=['nose', 'rednose'],  # Allow proper nose usage with setuptols and tox
       **extra_opts
 )

tox.ini

@@ -6,6 +6,8 @@ envlist = {py26,py27,py32,py33,py34,pypy,pypy3}-{mg27,mg28}
 commands =
     python setup.py nosetests {posargs}
 deps =
+    nose
+    rednose
     mg27: PyMongo<2.8
     mg28: PyMongo>=2.8,<3.0
     mg30: PyMongo>=3.0