Add PyPI setup file

Add metadata file for PyPI and specify readme file.

README.md

@@ -14,7 +14,13 @@ This ensures that the code snippets work as intended.
 
 # Installation [![build status](https://srv.sauerburger.com/esel/doxec/badges/master/build.svg)](https://srv.sauerburger.com/esel/doxec/commits/master)
 
-You can simply clone the repository and run the setup script to get doxec.
+You can install the package using pip
+
+```bash
+$ pip install doxec
+```
+
+or you can clone the repository and run the setup script to get doxec.
 
 
 <!-- console 

setup.cfg

+[metadata]
+description-file = README.md

setup.py

@@ -14,6 +14,7 @@ setup(
     packages=['doxec'],
     scripts=['bin/doxec'],
     test_suite='doxec.tests',
+    url="https://gitlab.sauerburger.com/frank/doxec",
     classifiers=[
         "Development Status :: 3 - Alpha",
         "Environment :: Console",