Draft: Merge version0.1 changes into dev

Working plotID package version 0.1.0 with basic functionality. It is ready for testing according. This can be done with the instructions from the README.

tests/test_create_id.py

 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
-'''
+"""
 Unittests for CreateID
-'''
+"""
+
 import unittest
 from create_id import create_id
 
 
 class TestCreateID(unittest.TestCase):
+    """
+    Class for all unittests of the create_id module.
+    """
 
     def test_existence(self):
+        """Test if create_id returns a string."""
         self.assertIsInstance(create_id(1), str)
         self.assertIsInstance(create_id(2), str)
 
     def test_errors(self):
+        """ Test if Errors are raised when id_method is wrong. """
         with self.assertRaises(ValueError):
             create_id(3)
         with self.assertRaises(ValueError):
             create_id('h')
 
     def test_length(self):
+        """ Test if figure_id has the correct length. """
         self.assertEqual(len(create_id(1)), 10)
         self.assertEqual(len(create_id(2)), 8)