New functions and small refractors.

New functions

• substr()
• is_iterable()

Removes some unnecessary and redundant code in sort().
Rename and convert CHANGES to CHANGES.rst and use reStructuredText.

Refactor and new release.

Refactor of common_subsequence(), longest_common_subsequence() and shortest_common_subsequence() into one function, common_sub(), where also test_stringhelpers.py is updated according to this.

Small refactor of reverse_order()
Small refactor of odd() and even()

New functions, small refactor of odd() and even(). Adds test case.

New functions

• sort()
• common_subsequences()
• longest_common_subsequence()
• shortest_common_subsequence()

Small refactoring of odd() and even().

Adds test_stringhelpers.py

Improves the `reverse()` and `reverse_order()` functions.

1.2.1

Bumps the version number and updates CHANGES

Improves the `upcase_first_letter()` function.

1.2

Improves the upcase_first_letter() function

First release.

1.0

Updates README.md with install instructions