Fix Python packaging which previously included the "tests" package

After reading thought https://packaging.python.org and
https://docs.python.org/3/distutils/ again, I decided to continue using
the `find_packages` helper function because this make copy and paste
easier when I decide to reuse this little project as a template for the
next Python project. But ensure that Python packages like tests and docs
are not installed by excluding them.
It is directly used from the example given here: https://packaging.python.org/distributing/#packages

Also add `package_data` to ensure that the Jinja2 templates of the
package are included.

Now only the "yaml4rst" package is installed which can be quickly
verified by `pip3 uninstall yaml4rst`:

```
Uninstalling yaml4rst:
  /usr/local/lib/python3.5/dist-packages/yaml4rst-0.1.1.dist-info/DESCRIPTION.rst
  /usr/local/lib/python3.5/dist-packages/yaml4rst-0.1.1.dist-info/METADATA
  /usr/local/lib/python3.5/dist-packages/yaml4rst-0.1.1.dist-info/RECORD
  /usr/local/lib/python3.5/dist-packages/yaml4rst-0.1.1.dist-info/WHEEL
  /usr/local/lib/python3.5/dist-packages/yaml4rst-0.1.1.dist-info/entry_points.txt
  /usr/local/lib/python3.5/dist-packages/yaml4rst-0.1.1.dist-info/metadata.json
  /usr/local/lib/python3.5/dist-packages/yaml4rst-0.1.1.dist-info/top_level.txt
  /usr/local/lib/python3.5/dist-packages/yaml4rst/__init__.py
  /usr/local/lib/python3.5/dist-packages/yaml4rst/__pycache__/__init__.cpython-35.pyc
  /usr/local/lib/python3.5/dist-packages/yaml4rst/__pycache__/_meta.cpython-35.pyc
  /usr/local/lib/python3.5/dist-packages/yaml4rst/__pycache__/cli.cpython-35.pyc
  /usr/local/lib/python3.5/dist-packages/yaml4rst/__pycache__/defaults.cpython-35.pyc
  /usr/local/lib/python3.5/dist-packages/yaml4rst/__pycache__/helpers.cpython-35.pyc
  /usr/local/lib/python3.5/dist-packages/yaml4rst/__pycache__/reformatter.cpython-35.pyc
  /usr/local/lib/python3.5/dist-packages/yaml4rst/_meta.py
  /usr/local/lib/python3.5/dist-packages/yaml4rst/cli.py
  /usr/local/lib/python3.5/dist-packages/yaml4rst/defaults.py
  /usr/local/lib/python3.5/dist-packages/yaml4rst/helpers.py
  /usr/local/lib/python3.5/dist-packages/yaml4rst/reformatter.py
```

Related to: #1
Thanks to: @ganto

CHANGES.rst

@@ -12,6 +12,16 @@ yaml4rst master - unreleased
 
 .. _yaml4rst master: https://github.com/ypid/yaml4rst/compare/v0.1.1...master
 
+Fixed
+~~~~~
+
+- Python packaging which previously included and installed the unit tests as
+  separate "tests" Python package.
+  Now the built distribution release (Wheel) only contains the actual Python package
+  "yaml4rst" without the unit tests. Checkout the source distribution or the
+  git repository for hacking on the project.
+  Thanks very much to ganto_ for reporting and providing a patch! [ypid_]
+
 
 `yaml4rst v0.1.1`_ - 2016-11-05
 -------------------------------

docs/includes/global.rst

@@ -919,6 +919,44 @@
 .. _debops.directories: https://github.com/debops/ansible-directories
 .. ]]]
 
+.. DebOps People [[[
+
+.. Link target preference:
+   1. DebOps People
+   2. DebOps Wiki
+   3. GitHub profile
+   4. Any HTTPS URL
+   5. Any legacy HTTP URL
+
+.. _DebOps People: https://docs.debops.org/en/latest/debops-keyring/docs/entities.html
+
+.. _drybjed: https://docs.debops.org/en/latest/debops-keyring/docs/entities.html#debops-keyring-entity-drybjed
+.. _ypid-ansible-common: https://github.com/ypid/ypid-ansible-common/
+.. _ypid-ansible-inventory: https://github.com/ypid/ypid-ansible-inventory
+
+.. _le9i0nx: https://docs.debops.org/en/latest/debops-keyring/docs/entities.html#debops-keyring-entity-le9i0nx
+
+.. _AnBuKu: https://github.com/AnBuKu
+.. AuBuKa aka. hugi
+
+.. _ganto: https://github.com/ganto
+.. _htgoebel: https://github.com/htgoebel
+.. _nickjj: https://github.com/nickjj
+.. _scibi: https://github.com/scibi
+.. _do3cc: https://github.com/do3cc
+.. _thiagotalma: https://github.com/thiagotalma
+.. _mbarcia: https://github.com/mbarcia
+.. _jacksingleton: https://github.com/jacksingleton
+.. _ser: https://github.com/ser
+.. _yuvadm: https://github.com/yuvadm
+.. _pedroluislopez: https://github.com/pedroluislopez
+.. _patrickheeney: https://github.com/patrickheeney
+.. _rchady: https://github.com/rchady
+.. _tallandtree: https://github.com/tallandtree
+.. _zpfvo: https://github.com/zpfvo
+
+.. ]]]
+
 .. External [[[
 
 .. Link target preference:

setup.py

@@ -51,7 +51,8 @@
         'Topic :: Text Processing',
     ),
     keywords='YML YAML RST reStructuresText Ansible DebOps linting docs documentation',
-    packages=find_packages(),
+    packages=find_packages(exclude=['contrib', 'docs', 'tests*']),
+    package_data={'yaml4rst': ['*.j2']},
     install_requires=[
         # Debian packages: python-yaml python3-yaml python-jinja2 python3-jinja2
         'PyYAML',