Minor fixes to readme and setup

1) Add version badge
2) Remove inconsistent full stops
3) Add classifiers to setup

README.rst

-|pipeline status| |coverage report| |pypi|
+|pipeline status| |coverage report| |pypi| |version|
 
 Tupak
 =====
@@ -7,8 +7,8 @@ Fulfilling all your gravitational wave dreams.
 
 -  `Installation
    instructions <https://monash.docs.ligo.org/tupak/installation.html>`__
--  `Contributing <https://git.ligo.org/Monash/tupak/blob/master/CONTRIBUTING.md>`__.
--  `Documentation <https://monash.docs.ligo.org/tupak/index.html>`__.
+-  `Contributing <https://git.ligo.org/Monash/tupak/blob/master/CONTRIBUTING.md>`__
+-  `Documentation <https://monash.docs.ligo.org/tupak/index.html>`__
 -  `Issue tracker <https://git.ligo.org/Monash/tupak/issues>`__
 
 We encourage you to contribute to the development via a merge request.  For
@@ -21,4 +21,6 @@ us directly.
 .. |coverage report| image:: https://monash.docs.ligo.org/tupak/coverage_badge.svg
    :target: https://monash.docs.ligo.org/tupak/htmlcov/
 .. |pypi| image:: https://badge.fury.io/py/TUPAK.svg
-   :target: https://badge.fury.io/py/TUPAK
+   :target: https://pypi.org/project/TUPAK/
+.. |version| image:: https://img.shields.io/pypi/pyversions/tupak.svg
+   :target: https://pypi.org/project/TUPAK/

setup.py

@@ -79,4 +79,9 @@ setup(name='tupak',
           'scipy'],
       entry_points={'console_scripts':
                     ['tupak_plot=cli_tupak.plot_multiple_posteriors:main']
-                    })
+                    },
+      classifiers=[
+          "Programming Language :: Python :: 2.7",
+          "Programming Language :: Python :: 3.7",
+          "License :: OSI Approved :: MIT License",
+          "Operating System :: OS Independent"])